Holes in tail fin?

[smallvle]

My betta Seuss has a little cave in his tank (2.5 gal,) that he's had for the year i've had him, and said cave has two small plastic plants on top of it that he's never ever had a problem with before; but I noticed a week or so ago that he has two small holes in his tail fin. He doesn't seem bothered by them, and looks ok otherwise. He loves his cave, and it is the perfect size for his tank, but I was wondering if there is anything I can do for his rips to make the fin grow back or keep it from ripping worse. I don't think I can remove the plants without leaving a really sharp chunk of plastic. And i'd rather not get rid of his cave if I don't absolutly have to. Like I said, this is the first problem wtih it in a year. (The plants are the only thing in his tank that would be capable of ripping his fins.) Thanks!