Extreme Jaw Pain After Prep Work for Veneers and Installation, Normal?

there is nothing to do,on timing, it takes a while to set 18 veneers, properly,

but there could be a chance always to present this, there are very strong antinflamatories, that will help , what i recommend you to do, its to see a tmj specialist, and there is some fisiotherapy for this type of situations, 

You definitely need to pursue more solutions, a bite guard and antiinflammatory medications may be indicated. Do make sure your joint is evaluated to differentiate between muscle spasm and a joint disorder. Good Luck!

It's very possible that you may be experiencing TMJ symptoms from keeping your mouth open wide for so long. Have your dentist evaluate you for TMJ.