Could the collar be making her itch?
I got a second dosage of the flea treatment from the vet and put it on her as I noticed she was scratching, but I put the treatment on around 10:00 am Tuesday and it is now 10:00 pm Wednesday and she is scratching around her neck still. It isn't constant, but it makes me wonder if the collar could be making her itch or the fleas suddenly are immune?
I haven't actually seen fleas since the beginning of the month right after her first treatment. I thought I saw one last week which is why I got another dose. I took the collar off before applying the treatment and left it off until later than night.