How Can Cold, Sore Throat, Congestion With A Rash Be Treated?

I have had a bad cold and sore throat this week. I have been taking advil cold and sinus since tuesday. Yesterday I only took one dose of it and I woke up with a rash this morning. Still slightly congested and a slight sore throat but I wasn t sure if the rash could be from not taking the medication anymore or maybe a symptom to something more severe