You will be using the ingredients you gather from this quest in the next quest. Failed combines consume the items. Consider harvesting at least twice the required amount (10) of each item to avoid gathering again if their combination fails. (PLEASE NOTE: You can only harvest 5 of the bracket fungus; after 5, the fungus is no longer clickable. The other two items can still be harvested beyond 5).
Also, consider bringing at least 5 smoldering candles with you when you work on this quest so you can do the next step of this questline immediately after turning this one in.