5 days after hair transplant - is this normal, or an infection? I have a large, pus-filled pimple in recipient area (Photos)

If you are having issues after surgery, especially with "pus" you need to contact your doctor.  It is not normal but it is treatable.

Infections are unusual after hair transplantation.  However, if you are seeing pus, or have any questions regarding a possible infection, it is always best to be evaluated by your surgeon. Occasionally, one of the transplanted hairs can become ingrown, and an infection can occur. Thanks for sharing!

It is best to follow up with your hair transplant physician. It might be a folliculitis or just accumulation of sebum from hair oil glands.  At times the oily secretions of the hair glands cannot find their way out and develop a collection. Post hair transplant infections are rare, but they can occur and you need to be evaluated by your doctor. 

large, pus-filled pimple in the recipient area is not a normal part of the healing process, you should  be concerned that you might have a small, (easy to cure) beginning of an infection

Follow up with the Physician who transplanted you in order to rule out infection, It is also important to follow any post-op instruction such as taking the recommended antibiotics to avoid any infection. Best of luck.