THANK YOU!! i can explain/summarize the potion ending below
(SPOILERS)
basically it's revealed that the potion is behind mary's curse, and since you've spent the entire game making the potion hazel takes it so she can be with mary forever and so that she can understand the pain mary goes through, but it fails because messing with potions is dangerous (and also it isn't a full moon). mary is still thankful though bc this is the first time someone's stuck with her and showed her love