Smile messed up after Dysport injection in masseters. Did my injectionist mess up, did I mess up by sleeping on side?

This may be due to Botox placement. Botox results last for 3-4 months in new areas of treatment. If you're unhappy with your final results, venus legacy treatments can help soften results. See an expert. Best, Dr. Emer

I hope this was done by a licensed physician. The before and after pictures differ in chin position and this is likely to account for the difference in appearance.  The Dysport will wear off in several months and the effects will not be permanent.  You don't need your masseter muscles treated.  Don't do this service again.

Injectable neuromodulators can migrate and affect other muscles where it was not the intention to do so. Your face sleeping could be a contributing factor. As the product migrated there and was not a direct injection, this effect on you risorius muscle should be limited. Best wishes, Dr. ALDO  

Thank you for the question and pictures.   It appears, based on your pictures, that the Dysport migrated a little.  Rest assured that this asymmetry isn't something that will draw gazes from across an auditorium.  This effect will likely wear off before the massater effect, as there is presumably less material in the area that affects your smile than the massater muscle.  Good luck! 

Botulinum toxin treatment into the masseter muscle is a powerful tool to help to reshape the face, especially in patients with strong muscles (gum chewers...) unfortunately, as in treatments in other parts of the face, misplacement of toxin can cause unintended issues. luckily in the lower face these usually resolve within a few weeks.
this was definitely not because you slept on that side though.
good luck!