I'm not a doctor (I should have that as a shortcut on my keyboard now :-)) so am not in a position to give you an answer about seeing a physician. What I can do though is point you to literature from the Academy of Dermatologists as well as from other noted experts in the field. Generally, one should consider oral steroids if the rash is on the face, private areas, or covers more than 30% of the body. The length of the prescription is VERY important here as if the course is too short you could end up with a harsher rebound rash. The recommendations I've seen have been for a 14 day minimum (or longer) course of oral steroids.
If you see the doctor, discuss exactly what he/she is prescibing, duration of the prescription, side effects, and of course what your expectations should be for this treatment. If you do not fall into the above category for generally needing an oral steroid, then the decision is up to you. If you chose to deal with the rash with the help of a physician, consider some of the treatments listed in the Treatments section on this site. Realize that how people respond to treatment varies so I can't really give you any one treatment and necessarily expect it to work for you 100% or every time.
Now for your reading pleasure: