Just over 2 months post op. Why is my hair growing patchy and not all over? The hair itself is long

2 months after surgery is still too early to assess growth following hair transplantation. You should wait 12 months to assess true results as it takes some time for some of the embedded follicles to start growing hair which may account for the patchy growth you are noticing now. 

The hair follicles do not all waken at once. They tend to reawaken over a 6 month period and each hair will thicken over time. Not to worry at this point.

At 2 months, some of the hair has started to grow and other hairs have not. Just be patient and they all should grow out in a few more months