Problems after root canal

I had a root canal 3 weeks ago, the tooth was devital and abscessed.  It was tooth #5. Prior to surgery, I thought it was abscessed since it hurt to touch any part of my face near that tooth, extending from bottom of nose to mouth. Obviously, thought that face pain should go away after surgery, but it is still there.  When my face swelled, it was exactly where that face pain was, extending to under my jawline (seemed to follow a nerve??).  
My question is whether you think the abscess has been completely removed.  Should I have an MRI or scan by my medical doctor since my dentist just says he is not sure what to do (I won't let him cap it yet) and he says he does not do MRIs since he does not know how to read them...  Help, I just need a second opinion since I'm going thru tens of thousands of restoration cosmetric surgery to correct severe TMJ and bruxism over the yrs.

[Hamidreza Nassery , DMD, FICOI]

Suzy,
first off, your instinct of not putting a crown is good. Do not untill all issues resolve. From the sound of it it was quite an extensive infection. Please note the antibiotic regimen you were placed on. Also, remember, if you had that much swelling from the upper arch to below your jaw line, ( rather extensive) then expect that it will take some time to heal all the facia that was damaged and torn by the swelling. As far as MRI , unless there is any other medical reason, I believe it would be an overkill.. if the root canal looks good on the x-ray then at this stage do a lot of moist heat compress to the area to promote blood flow and healing.
Remember, healing is a process not and event.
All the best.