Retinal tear laser complications?

Low risk procedure. A retinal tear can be surrounded by laser, which helps to prevent retinal detachment. One complication is that the treatment is not adequate, and a detachment happens anyway. There can be some discomfort during the laser procedure, but there is virtually no risk of inflammation, and no risk of infection. It is remotely possible that the laser could be applied to an unintended part of the retina.
Might not take. Rarely it might not "take" and need to be repeated or another procedure performed. This is independent of the performing ophthalmologist.