No matter what method is used to open the skin, it incision has to heal, and that is when the scar tissue is formed. Though there are several ways of making an incision and each states that is "reduces" scarring, none can eliminate a scar from forming.
How much scarring that occurs depends upon several factors. Host factors such as whether or not the patient is a keloid former are probably the biggest. Others include how the tissues are handled during the procedure, where the incision is placed within the skin tension lines, absence of infection, etc.
So, probably, the best method to prevent a scar is to approach the mass from inside the mouth.
You should see a plastic surgeon or a maxillofacial surgeon for an evaluation. One of the biggest risks with surgery in the cheek region is damage to on of the facial nerves. If a motor nerve is injured, you could lose the function of some of the muscles. This can cause the mouth to droop, not being able to smile, or move the lips on that side, etc. So, it is important to have a surgeon that is well trained in facial surgery do the procedure. Plastic and maxillofacial surgeons are so trained. Plastic surgeons do face lifts and other procedures that have to avoid these nerves. As do the maxillofacial surgeons. The other risk is to the parotid glands and salivary glands in the cheek.
This may be why the first time the cyst was only drained and not removed. The surgeon may have felt that it was too risky to the nerves and glands, to remove the cyst wall, so a small incision was made and the cyst contents were drained.
Again, speak to a plastic or maxillofacial surgeon about the mass. Good luck.