Thanks for using Petco Pet Education Center, formerly Petcoach! This looks like a focal infection. You can try to use chlorhexidine containing pads (such as the Douxo chlorhexidine 3% PS pads) to clean the are twice daily for 7 days. You may find these online or at your local pet store. If there is no improvement or in the meantime this appears to be getting worse, have her evaluated by a veterinarian for further assessment and treatment. Good luck and have a good night!