Yep its best course of action tbh, daily water changes and keep dosing the meds, clean water is the best thing for her, hopefully nothing nasty got in the wound to cause it to get worse, its normal(ish) for wounds to appear worse before they get better, they often go fluffy as the scales start to grow back, least thats what Ive found, particularly with severums, when Harry caused Vinny some serious injuries, they looked very bad and it took a while for them to heal completely, but to look at him now, you would never know.