As a fellow sufferer of social anxiety over the past 25 years, I can tell you that any alleviation of such symptoms will likely be a result of coming to understand yourself better as opposed to the specific neurological action of DMT.
DXM was a wonder drug for my anxiety, but it fit the latter pattern I stated above. The effects would wear off, leaving me in a worse situation of having felt no anxiety for a few days and then being thrust back into the fray without really understanding any better why I would get anxious in the first place. I DO NOT recommend going this route - just throwing the info out there for comparative purposes.
I don't think a single dose of DMT would be highly effective in alleviating your anxiety, but then again - it very well could. It will surely open your mind to the inner workings of your interpersonal relationships, and likely shed some light on the source of the anxiety. The realization of there being no reason at all for it could be an epiphany that DMT is very well suited to bring about. It may take some time, though. Even working up with small doses, I've had a few rough rides - but even the rough ones will leave you glad you did it. My mildly 'bad trips' have, as a matter of fact, been the most revealing on matters of psychological issues.
The after effects of DMT have been very manageable for me. About an hour after a trip, they are practically non-existent besides the memories of the experience. Integrating those memories could be a significant hurdle if you are not experienced with psychedelics - and if so, starting out low and slow is highly advised. In terms of risk - if you consider being able to approach very deep conversations with loved ones shortly after a trip with no anxiety at all a risk - then yeah, there are risks a plenty
I like to think of social anxiety as stemming from a subconscious desire to be in control of certain social situations. DMT has a very profound ability to show us exactly how futile trying to control anything but our own actions can be. Once you are able to begin letting go of that desire for control, you can start building upon the ability to accept and be at ease with that which you cannot control.
If a Shaman/sitter is needed depends entirely on you and prior psychedelic experience. Since you are working with social anxiety issues, an unfamiliar person near you could turn out to be more of a bad thing than a good one. Although I always trip alone, I don't advise trying anything for the first time without someone trustworthy nearby that knows what's going on. I know, "Do as I say, not as I do!" right? I actually can't wait 'til my daughters are old enough for me to use that
