This has to be a fungus infection of some kind brought on by taking the antibiotics. Your sugar intake should go to near zero for two weeks; that includes breads, potatoes, and fruits. Fungus loves sugar to eat, so you need to starve it. Secondly, get some probiotic pills from a health food store. The pills should have at least 3 different types of bacteria. At least one of those will like to eat the fungus in your gut. Thirdly, use hydrocortisone cream to cut the itch. Use it sparingly because that cream can promote fungus growth, but it is important to stop the itch. Sometimes an ice cube can act to stop the itch fast so the cream has time to work.

If things clear up, don't stop for at least two weeks, and it might take a good month to work.

You may find it comes back after a few weeks of stopping the probiotic pills. If it does, then start again with the pills and zero sugar for another two weeks.

Fungus infections can take a while to beat.