In the frog village there's a merchant who sells healing potions. Also, if the fights seem too difficult, maybe it makes sense to think about your equipment. What's your level?
I got past it eventually with a lot of save and loads. I was only 6 or 7 and i already had the best gear i could get at that point or at least make, the issue is touch controls on mobile are really bad, sorry. Only real complaint, Seems like half the areas you click on wont count as a move except sometimes the same spot works if you click it while standing in a different spot and if you use the buttons instead and your finger just barely comes off the d-pad you might run randomly across the area. so avoiding fights was a huge pain and it was 3 on 2 while i missed most attacks.