Sinclair's Request

I’m lvl 41 and doing the Boombling Island quests. When doing “Sinclair’s Request” by accident I pressed exit before getting the fruit and now it wont transform me back into a Pebbling to go into the cave. I bought the potion but it’s only for lvl 50. I clicked every inch of the map and nothing. Talking to Sinclair only opens the shop. Abandoning quest and accepting again doesn’t solve it.

Did you find an answer to this problem?