How long does it take for the numbness go away after ulnar nerve decompression in right elbow? It's been 5 months since the surgery!

Some general rules. If the nerve coverings, called myelin are the sole nerve disorder, recovery of myelin takes 3-4 weeks, with total return to mostly normal function. Yet, if the central wire, axon, is involved, recovery proceeds at speed of fingernail growth, about 0.1 mm daily. An EMG can provide objective numbers to assist prognosis, and is worthwhile doing at this point.