If you had searched for "healslut" before posting your question, you would have found
this post (long post, but towards the end there's a part about "HealSlut"), where 0x52 explains, that the developers of that game broke Ren'Py by using a reserved variable, and there's nothing he can do about that.
Please do use the search at the very top before asking about games -- the chances are high, that you're not the only one with an issue, and there might already be an answer within this thread (
this also might help with searching threads). Thank you!