I am allergic to Biogel, Shellac & nail glue. Any advice on how to grow out a split nail please?

Hi there. Are you also allergic to acrylic too? If so you could try and put a strip of fibre glass or silk onto the split with a couple of coats of thick top coat. If you keep applying a coat each day so it doesn't lift. Hopefully this should give you some time or your nail to grow out. Hope it helps. Tracey x