In this case, when you're standing on the acid tile, you need to press the 'NEXT' button. The acid will then deal one point of damage to you, and afterward you'll have another move, allowing you to step to the right and leave the tile.
oh lmao how did i not figure that out
This was actually very valuable feedback for me, because it will help me make the individual mechanics clearer next time. :)
I also didn't figure this out!