Is It Safe To Take Cefran Injection And Rynex Nasal Spray For Mouth Ulcer?

My doctor gave me rynex nasal spray to treat mouth ulcer. He also told me to take injection cefran (I took one yesterday and told me to take two more). Gargle with disprin ribson deltason crushed mixture and ribson for three times daily. He told me I should feel better after the first shot. Which I am not at all. My question is what has happened to me and what has been instructed is this ok?