I'm guessing about 3 weeks old. I'm not sure how long it takes CA quail to mature, but at this time of year I don't think it will need supplemental heat much longer.
Is there a wildlife rescue you can contact? In most states you need a permit to keep native species of quail. You are...
How old is the chick?
What is the brooder setup?
What are you using for bedding?
What is the temperature at chick level on the warm side? The cool side?
Unfortunately, it is possible that there is simply something wrong with the chick. You might try some Nutri-Drench or some boiled, crushed...
There are a few things that can cause the baldness. An overenthusiastic male is one. Feather plucking is another. Excess heat can cause some as well.
Feather plucking can be aggression, it could also be insufficient protein in their diet.
I'm so sorry for what happened. I'm not particularly fond of raccoons myself since they took out all of my chickens last fall.
You learned the hard way, but you're not going to make the same or similar mistake again.