diff --git a/src/battle-scene.ts b/src/battle-scene.ts
index bb4803a9eb1..c94522d3af5 100644
--- a/src/battle-scene.ts
+++ b/src/battle-scene.ts
@@ -1653,8 +1653,9 @@ export default class BattleScene extends SceneBase {
 		return Math.floor(moneyValue / 10) * 10;
 	}
 
-	addModifier(modifier: Modifier, ignoreUpdate?: boolean, playSound?: boolean, virtual?: boolean, instant?: boolean): Promise<void> {
+	addModifier(modifier: Modifier, ignoreUpdate?: boolean, playSound?: boolean, virtual?: boolean, instant?: boolean): Promise<boolean> {
 		return new Promise(resolve => {
+			let success = false;
 			const soundName = modifier.type.soundName;
 			this.validateAchvs(ModifierAchv, modifier);
 			const modifiersToRemove: PersistentModifier[] = [];
@@ -1664,20 +1665,20 @@ export default class BattleScene extends SceneBase {
 					modifiersToRemove.push(...(this.findModifiers(m => m instanceof TerastallizeModifier && m.pokemonId === modifier.pokemonId)));
 				if ((modifier as PersistentModifier).add(this.modifiers, !!virtual, this)) {
 					if (modifier instanceof PokemonFormChangeItemModifier || modifier instanceof TerastallizeModifier)
-						modifier.apply([ this.getPokemonById(modifier.pokemonId), true ]);
+						success = modifier.apply([ this.getPokemonById(modifier.pokemonId), true ]);
 					if (playSound && !this.sound.get(soundName))
 						this.playSound(soundName);
 				} else if (!virtual) {
 					const defaultModifierType = getDefaultModifierTypeForTier(modifier.type.tier);
 					this.queueMessage(`The stack for this item is full.\n You will receive ${defaultModifierType.name} instead.`, null, true);
-					return this.addModifier(defaultModifierType.newModifier(), ignoreUpdate, playSound, false, instant).then(() => resolve());
+					return this.addModifier(defaultModifierType.newModifier(), ignoreUpdate, playSound, false, instant).then(success => resolve(success));
 				}
 				
 				for (let rm of modifiersToRemove)
 					this.removeModifier(rm);
 
 				if (!ignoreUpdate && !virtual)
-					return this.updateModifiers(true, instant).then(() => resolve());
+					return this.updateModifiers(true, instant).then(() => resolve(success));
 			} else if (modifier instanceof ConsumableModifier) {
 				if (playSound && !this.sound.get(soundName))
 					this.playSound(soundName);
@@ -1700,19 +1701,26 @@ export default class BattleScene extends SceneBase {
 						if (modifier.shouldApply(args)) {
 							const result = modifier.apply(args);
 							if (result instanceof Promise)
-								modifierPromises.push(result);
+								modifierPromises.push(result.then(s => success ||= s));
+							else
+								success ||= result;
 						}
 					}
 					
-					return Promise.allSettled([this.party.map(p => p.updateInfo(instant)), ...modifierPromises]).then(() => resolve());
+					return Promise.allSettled([this.party.map(p => p.updateInfo(instant)), ...modifierPromises]).then(() => resolve(success));
 				} else {
 					const args = [ this ];
-					if (modifier.shouldApply(args))
-						modifier.apply(args);
+					if (modifier.shouldApply(args)) {
+						const result = modifier.apply(args);
+						if (result instanceof Promise) {
+							return result.then(success => resolve(success));
+						} else
+							success ||= result;
+					}
 				}
 			}
 
-			resolve();
+			resolve(success);
 		});
 	}
 
diff --git a/src/modifier/modifier.ts b/src/modifier/modifier.ts
index de4477a3e68..1dde041b782 100644
--- a/src/modifier/modifier.ts
+++ b/src/modifier/modifier.ts
@@ -1001,9 +1001,11 @@ export class PokemonHpRestoreModifier extends ConsumablePokemonModifier {
       if (this.fainted || this.healStatus)
         pokemon.resetStatus();
       pokemon.hp = Math.min(pokemon.hp + Math.max(Math.ceil(Math.max(Math.floor((this.restorePercent * 0.01) * pokemon.getMaxHp()), restorePoints)), 1), pokemon.getMaxHp());
+      
+      return true;
     }
 
-    return true;
+    return false;
   }
 }
 
diff --git a/src/phases.ts b/src/phases.ts
index f668278d273..08e4f1d6999 100644
--- a/src/phases.ts
+++ b/src/phases.ts
@@ -4162,10 +4162,15 @@ export class SelectModifierPhase extends BattlePhase {
       const applyModifier = (modifier: Modifier, playSound: boolean = false) => {
         const result = this.scene.addModifier(modifier, false, playSound);
         if (cost) {
-          this.scene.money -= cost;
-          this.scene.updateMoneyText();
-          this.scene.playSound('buy');
-          (this.scene.ui.getHandler() as ModifierSelectUiHandler).updateCostText();
+          result.then(success => {
+            if (success) {
+              this.scene.money -= cost;
+              this.scene.updateMoneyText();
+              this.scene.playSound('buy');
+              (this.scene.ui.getHandler() as ModifierSelectUiHandler).updateCostText();
+            } else
+              this.scene.ui.playError();
+          });
         } else {
           const doEnd = () => {
             this.scene.ui.clearText();