Wondering if it's necessary to go to a specialist to get a crown lengthening?

Depends: It all depends on the skill of your general dentist and his/her comfort in performing the procedure. Many general dentist will perform the lengthening, and the rest will refer to a periodontists. In the end, it's what's best for your health.

Any general dentist: If it's indicated procedure any dentist can perform the crown lengthening. It is generally performed in order to improve the health of the gum tissue, or to prepare the mouth for restorative or cosmetic procedures. Good luck.