I am 18, have never suffered from acne, I get the occasional pimples here and there just pretty normal average teenage skin, but 2 days ago I went on a bush walk it was really hot when I came back I noticed my skin was a little lumpy on my lower checks, very suddenly it became red & angry, I feared it was acne but my mum says it's a rash. It gets itchy from time to time and I can feel it tingling on my face! What is this & how do I get rid of it?!