A sligth down curved penis, anything to see a doctor about?

Only you can say. The thing that determines if penile curvature is sufficient to warrant medical intervention is whether or not it interferes with sex. If you can have sex without difficulty, then adapt to the situation. If you can't have sex without consternation, see a urologist to discuss evaluation and treatment options.
Depends. It depends upon the curve. There is a medical condition which can cause a curve in the penis, and there is a treatment -- however, first you need to see your doctor or a urologist and find out if that's your diagnosis.