while unlikely that you still have significant swelling (and asymmetric swelling at that), it certainly has to be discussed with you being less than half a year out of surgery. that being said, should you still have asymmetry in a few months revision would certainly be do-able. With it being intraorally placed, depending on how the incision was made and which implant was used/how was it fixed they can shift a fair bit more than extraoral incisions. As has been mentioned before, the most common cause for asymmetry after chin implant, however, is asymmetry BEFORE chin implant. Therefore, a good sound exam and examination of preoperative pictures is very important. I would suggest to you that you let things heal, keep your doctor involved and let him know of your concerns. If there are any issues later on, certainly consider a revision with a different chin implant or sliding osteotomy as that can be a great way to address mandibular bony asymmetry. hope this helps.
Most patients who have asymmetric chin implant, in general, they have an underlying bone asymmetry in the chin and would be good candidates for removal of the implant and chin advancement with a sliding osteotomy, which is very versatile and the asymmetry could be corrected easily. It is possible that you did not have any bone asymmetry. Regardless, I still would suggest removal of the implant and a sliding osteotomy to aim for an optimal outcome.
Surgical option: Removal and replacement correctly. Non Surgical: use fillers or fat grafts to give a better symmetrical appearance.