It could be local irritation and may or may not be related to the treatment. It does look "quiet" in the image provided though. Keep an eye on it, watching for redness, discharge or spread. You can clean it daily using a diluted Betadine or chlorhexidine (Hibiclens) solution. If there are any significant changes or if Miss Pebbles is scratching excessively, then she should be physically examined by your veterinarian.