My 11 Year Old Daughter Is A Swimmer And Recently

My 11 year old daughter is a swimmer and recently has started getting red marks and slight cuts below her armpits on the line of her swimsuit. We bought her a new larger suit as her previous ones were getting small. The marks are continuing and remain for a few days. She was hospitalised for 2 weeks at 1week old with severe impetigo and has very sensitive skin as a result. Could she be developing an allergy to the Lycra in the swimsuit? Or do I need to get this investigated further?