Sounds like the perfect situation for veneers. Your dentist will evaluate the grooves and may suggest a whitening procedure prior to veneers if the grooves are much darker than your surrounding enamel. They will evaluate your "bite" and check for para-functional habits like tooth...
Veneers that are covering the tooth can not cavity, but your tooth that is supporting the veneer can get cavity.
In most cases the veneer can be saved by removal of the cavity and bonding the filling to the existing tooth. Depending on where the cavity is, the dentist and you will make a...
Veneers can be made to match the surrounding teeth. How well they match depends upon the ability of the dentist and his technician. Before having veneers made ask to see photographs of veneers made by the dentist for other patients.