Hi Linda, I've got one of these on my thumbnail too.
If it's always there then it's probably caused by some kind of trauma or it's hereditary. I think mine's hereditary because my mum's thumbs are like this too. Flippin' hurts when you catch it too - most of the time I put a strip of silk or fibreglass over it if I've not got nails on for some reason - like this week cos I've been busy in the garden.
If it's just a temporary split then you should be ok when it grows out - and it serves ya right for biting off all your enhancement today! *LMAO* :twisted: