What Causes Itching On Head And Face While On Flucloxacillin?

i have got impetigo in my hair and on my eye started taking flucloxacillin yesterday and im so itchy all over my head and face i no i am not allergic to these tablet as i have had them before for other things, does impetigo usually get worse before it gets better and can i take some allergy tablets to relieve the itch?