Rat facial wound

We noticed our pet rat had this facial lump in the middle of February. We took her to the vet on 2/28 and the vet thought it was a mammary tumor that migrated to her face or a dental abscess. We were given sulfamethooxazole-trimethoprim and meloxicam and have been giving it to her as directed. Today the facial wound opened up like this and we were wondering what we can immediately do to make her more comfortable. Our vet opens at 8am and will get her in immediately, but should we clean it? Or try to prevent her from grooming it? Any advice is appreciated. Thank you!