What an awful DM. I can't find any TTRPGs that have a "heal wounds" spell, and I definitely can't find any that have a player roll a d20 to see how effective their healing is, but assuming this is 5th edition D&D, this is within the bounds of Lesser Restoration. Still, I'd be pissed if my character had some medical condition as part of their story, and another player just cast a spell to get rid of it