For torn fins, I'd make sure the water is very clean and watch for infection. As long as the fins do not get infected, they'll be okay.
If it's fin rot, I'd medicate the fish. I don't know which medication would be best off hand, but others can help or you can google it.
As to whether the fins will grow back, it depends on how much of the fins were damaged. If it's just the outer part, that normally grows back in time. But as the damage gets closer to the fish's body, then it's possible the fins won't grow back or will grow back distorted.
Whatever the case, the best thing you can do for them now is to give them the healthiest water possible. Make sure your tank is cycled with 0 ammonia, 0 nitrites, and low nitrates. Water changes are healthy.
Vicki Rena Filstar pimp #142 (four XP4s/three XP2s/one XP1) Eheim pimp #301 (Pro II 2128) Victor pimp #27 (VTS-253B-320)
90g - Journal
Pelvicachromis taeniatus 'Moliwe'
75g - Journal
Pelvicachromis pulcher 'Lagos Red' Better Pics 8-24
29g - Journal
Pelvicachromis pulcher 'unknown' --
29g - Pelvicachromis taeniatus 'Moliwe'
5g - RCS colony
2.5g - Journal