Swollen Lymphs Behind Ear, Rash On Neck, Body, Arms And Elbow, Not Itchy, Kp On Arms, No Stds, Had Mono. Lumpectomy For Precancerous Lump. Eczema Or Psoriasis?

Hi. I have two swollen lymphs behind left ear. Started 3 days ago. Since then a pimple like rash has spread from under my left ear down both sides of neck all over trunk of body reaching both side if arms real bad at inside of elbow. Non itching. I have history of mono. Lumpectomy in 2006 for precancerous lump (0). Diet no different, detergents soap shampoo no different. What could cause this. It s not eczema or psoriasis . I do have kp on back of upper arms but thats all. Could that spread?? And that fast? I have no stds (tested 3 months ago)