What worked for me was to get the cheap fake fingernail tips at Walmart and super glue them on, file them down short, and keep them on for 2-3 weeks. I kept extra glue in my purse if one fell off and would immediately glue it back on. If one came off and was lost, I would put a band aid around that finger tip until I could get home and glue another tip on. After a few weeks of it, the nails underneath were long enough that I would not bite them. I know super glue is not good for your nails but I was desperate. I will go 2-3 years with long nails and 1-2 years biting them to the quick (I return to biting them when they break and it spirals out of control). I have been doing it this way for 30 years or so. Good luck! It can be done.