Bumpy nail due to chewing

My 8 month old hasn't got any teeth yet but has shown signs off teething for MONTHS now (it's driving me mad I wish at least 1 would come through). This causes her to chew on her thumb alot, I give her all kinds of teething toys, she uses them for a couple of minutes and then goes back to her thumb. I stop her chewing it whenever I see it but I know she's doing it when I'm not there. Anyway, I was cutting her nails this morning and noticed her thumb nail is bumpy, I suspect this is to do with her chewing as the rest are fine but I'm not sure what to do about it? It's not painful or anything but I'm not sure if I should contact her doctor or just leave it as I assume she'll grow out of the chewing once some teeth come through. I only ask because I spoke to friends and family and no one else's child's had this.