Untreated, distichiasis can lead to corneal ulcers, chronic eye pain, excessive tearing, and eyelid spasms. It is almost certainly uncomfortable for the dog and permanent removal of the offending eyelashes is best when any clinical signs are present.
Surgery is done in a number of ways, depending on the number of lashes present and the preferences of the surgeon. Cryosurgery (freezing of the lid margin at the affected sites) can sometimes be done with a local anesthetic in a cooperative dog. There are other surgical options. Almost any surgery for this condition should be done with an operating microscope or good magnification so many general practitioners refer these cases to veterinary ophthamologists.
Postoperative care of inflammation from the surgery is usually necessary and should be planned for. There are usually two or three follow-up visits to check for regrowth of the eyelashes and removal of any that return or persist. In most cases, this can be treated with success. This makes life much more comfortable for your dog.