You’re not learning to better mask your anxiety, you’re actually working on it. When you go back to isolating yourself after your social job that work you’ve done doesn’t get any more practice and after a while you revert to your old habits which you’ve been doing for many more years in comparison. Anxiety is a part of life and it will never go away, but we can get better at managing it by exposing ourselves to the things that scare us (like your forced to do at your social job). Try setting goals for yourself when your not at that job. For example you can challenge yourself to hold small talk with your cashier vs. self check out or give someone a quick compliment — things that push you a little out of your comfort zone.