Betta Fish: Can I help him regrow his fins?

This is Lieutenant Dan. He had a decline in health recently and he is doing wayyy better now, but unfortunately his fin ended up mostly gone due to an infection after it tore. So my question is if there is anything I can give him that would help with the health and quality of his fins as they grow back? The little fin is growing rather quickly which im so happy about but I’m wondering if I can help with the rest of his fins that don’t look super awesome currently.