Persistent facial swelling after acne subcision?

38 years old man, underwent bilateral acne scar subcision using Nokor needle. There is significant improvement in acne scars, however after about 6 months, there are 2 cyst like non-tender, non-erythematous soft swelling on both buccal areas with the size of 4x4 cm. Looks like some fluid filled cysts, however aspiration does not return any fluid or blood. No US or MRI is done. 1. What would be the diagnosis? 2. What should be the next step? 3. What would be the treatment?