Suggest Treatment For Under Skin Rash

hello, i have just returned from holiday in turkey and used a prolonged suntan lotion P10. on day 2 i noticed a rash appear on my trunk, large red bumps however not itchy. the rash continued to spread all over my limbs during the next few days. i changed my sun lotion after 4 days (having eliminated other factors including face cream, face wipes, some foods etc) and the rash abated however have now been left with an underskin small rash still non itchy. What can i do?