Allergic to cold medicine?

ok when i was like 4 my mom gave me nyquil and i had rashes and my face had swelled up than a few years later she tried again when i was sick and said the same thing happened and took me to the E.R where they said it was an allergic reaction.About three years ago i took some without the main ingredient (dextramathortin) and i was fine, so my question is how can i tell (without dying) if i am still allergic? i do not want to go to the doctor( no insurance) i would just like to know a way i can tell.thanks and please excuse the spelling.