Thumb sucking and nail pulling

[caspered]

Can anyone offer advice? DD is three and quite confident and outgoing, but she is a big thumb sucker and pulls at all of her finger nails, it looks like she bites them, but she doesn't she just rips them off. Any advice, have promised nail varnish (childrens) etc if she grows her nails, but nothing works. Now she is starting to pull the skin around her fingers as well. HELP

I bite, chew pick at the skin around my finger nails too dont bite nails though, but still dreadful habit. It is just that though a habit.

If you find the answer let me know!