Talk to Dermatologist on Skin Allergy Due To Lycra

Doctor I purchased a bra that was made of 10% Lycra and 90% cotton & when I wore it, after 2-3 days I feel a very bad itching on my back, bust and shoulder with a little red bumps feels like rashes (picture attached). Firstly I think it's garmi daany so I was applying prickly heat powder on the effected arra. Now I took bath and I am just wearing cotton shirt without bra but still I am feeling so uncomfortable because of the itching and rashes/ daany chubhty hain jahan jahan effect hua hai bra ka..kindly suggest me medication for that.