The irritation could be from an allergy to spermicide. If the irritation is mild, try another type of spermicide.
Still not working? If the irritation is more severe or sticks around once you try different types of spermicide, think about trying a method that does not require any.
Try a different method: implant, IUD, Patch, Pill, Ring, injectable.
Society of Obstetricians and Gynaecologists of Canada. (2015). Canadian Contraception Consensus Chapter 5: Barrier Methods. JOGC Journal of Obstetrics and Gynaecology Canada , 37. Retrieved from https://www.jogc.com/article/S1701-2163(16)39376-8/pdf