Yesterday evening I noticed my dog was scratching her back a lot, then this morning I found several red tiny splotches/bumps along her back. The area feels a bit inflamed, I'm not sure if that's from all her scratching or if it's from the bites. She had a bath yesterday morning with her regular shampoo, and she is on flea and tick prevention. Her behavior is normal (apart from the scratching). Any idea what this could be?