Hi, I am 18 going on 19 and I know how you feel and I do/done what you do and that is scalp picking and scratching your head that make new ones.
I am in the same boat as you but after well I kept going to my doctor explaining that I have a scalp picking problem that he has given me this benovate scalp applicator and you may have used it but at the moment as a scalp picker I am not scratching my head as I use too, my nails are growing and my hair you see the results that it is turning healthy again I have had this problem since I was in year 5, so about nine years now and I can understand how you are feeling but seek help or what I have done is I read and watched someone who picked there head so much that puss came out there scalp and dripped down there face and they could see their skull and that really worried me so I went to the doctor and he gave me the scalp applicator and at the moment I am not scratching my head and I would do it at night as well I would use all sorts to stop the itching and then I would have scalps and a headache afterwards, so seek help or if that doesn't help talk to the people around you that's what I had done and now I am allowed to have perks like my hair getting dyed and cut because you can't have your hair cut now if you have scabs if it is an open wound.
Thank you for letting me tell my story and if you or anyone else has any questions don't be shy.
Whether it is from OCD or not, you do need to find a way to break the cycle of picking since obviously it has turned your life upside down. Do you see anybody for your GAD, depression or social anxiety? If so, then talk to them about some behavioral modification techniques. If not, then think about seeing a psychologist.
If you are at home, then I suggest wearing either a hat on your head or socks on your hands. I know it sounds stupid but you cannot pick if you either can't get to your head or you don't have your fingers avaialble. Also, you say you don't have fingernails so how are you picking to begin with? If they are long enough to pick, then cut them.
At work, you need to catch yourself when you are picking. You need to say STOP in your head and put your hands down. One poster once said she sits on her hands and that has helped her. Since you are doing it out of habit (even OCD compulsions can become habits) then you need to try to become aware of when you are doing it since you are more than likely doing it absent thought.
Hopefully you are seeing somebody and they can help you with the behavioral modification component of this.
Take care.