If i go ahead with this surgery to remove the bone re-growth on the third metatarsal, is there any guarantee it won't re-grow again?

Never a guarantee: If the bone re-growth is causing pain and interfering with normal function, then you should go ahead. However, with your history of an inflammatory arthritis like psoriatic arthritis, there is no guarantee that a re-growth can be avoided.

Yes: Regrow th is possible but not very likely. Depends where bone is removed and how much but is possible.