Hello! I went into the ER with a lump on my right shin over New Years and was given Keflex and Bactrim to treat the diagnosed Cellulitis. I have an allergy to Penicillan which presents as a rash. The ER docs knew that but thought I'd be ok. Pharmacist also indicated there was a 5% chance of a similar reaction to the Keflex. I was fine for 9 days, but on the eve of the 9th day of treatment, I started developing a rash. I finished out the Bactrim but discontinued the Keflex. Rash is worse 2 days later in that it has spread from armpits and groin areas to all of the underside of my arm, my back, and the inside of my legs down to my knees. There are also more red bumps. All are slightly itchy. I have no fever and am otherwise feeling fine. None of the bumps are any other color than red and none have broken skin. I'm pretty sure this reaction is an allergic reaction to one of the meds, but am not sure why it took so long for the symptoms to appear, so there's a little doubt. If it is an allergy, will this clear up on its own or do I need to head back to the Dr. for more meds? Should I add another allergy to my medical history? Thank you!