I can give you a fictional example of an experience I've been through and maybe the story could help you understand.
Around a year ago SWIM was prescribed Adderall for ADD/ADHD symptoms, however SWIM obtained them by lying to the psychiatrist about symptoms. SWIM started out low dosing everyday and within a short couple of weeks was binging heavily, snorting huge amounts and trying to chase that euphoria the first amphetamine dose produced.
SWIM continued this process for about 6 months, battling back and forth, having bouts of willpower and flushing 30 day supplies down the toilet, but to only refill a prescription to start all over again.
SWIM, before this, had minor symptoms of anxiety but nothing related to social anxiety. During the abuse and binging SWIM's perception changed significantly. At first SWIM only became paranoid under the influence of the amphetamines, but after the last binge and toilet flush he returned to a new psychiatrist and told him of the paranoia and extreme anxiety that the Adderall had produced. During this time SWIM was not under the influence but was beginning to display paranoia and social anxiety.
Conclusion that I have made about SWIM's mental status:
Research has shown that amphetamines can escalate certain mental disorders such as anxiety, schizophrenic, paranoia. I believe that abusing these stimulants carried SWIM's preexisting disposition over the threshold; producing a chemical change in SWIM's brain.
I have no theory or statistics as to if and when these symptoms will vanish. SWIM has not abused stimulants for over 2 years but SWIM states he still carries the symptoms daily.
SWIM although does state that the symptoms have decreased, and that he has good and bad days/weeks/months.
Psychiatrist prescribed clonazapam; which helped SWIM return to baseline. SWIM, being still engulfed by the "Dark Side" decided to abuse the benzodiazapine, but that is a whole other story.
Long story short SWIM, to this day, still battles with that same social anxiety and panic disorder that was brought forward by the Amphetamine abuse. SWIM still uses clonazapam, but however has been rehabbed from the "Dark Side" and can manage his own medicinal needs.
SWIM admits that cognitive behavioral therapy does help, but only with the addition of exposure therapy. The more SWIM interacts with others and puts his self into social situations, the more the symptoms become manageable.
Conclusion is that SWIM never before experienced social anxiety until abusing amphetamines. So my advise to you is to stay away from stimulants, or rather use them responsibly (if that's even possible)
There are also numerous support groups located on the internet as well as in treatment programs. It could be an option for you, in SWIM's experience the more he denies that symptoms and becomes afraid and isolates from the outside, the more the symptoms paralyze him; manifesting into panic situations/attacks.
I hope this helps, don't hesitate to message me if you'd like to talk more about the subject.