u/greenythebeast

I've been cat sitting for my parents for the past 3 months. When I took him in, he had this growth on the bottom of his chin. My Mom said she had brought him to the vet and he was given an antibiotic shot. However, it hasn't gone away over the 3 months I've had him. If I take a warm wet cloth and wipe the sore, the black crusty stuff usually falls off, leaving a pimple like sore that sometimes bleeds. Any ideas or suggestions? Much appreciated.