Sciatic nerve damage?

Hi to all nurses out there!!
First of all I am a newly registered nurse in our state and I'm just trying to review some of my notes and it just happen I came up with the intramuscular Injection Complications like the sciatic nerve damage.
Well, I'm just wondering if it could lead to permanent damage or if there is a chance to recover?
Another thing what site do you prefer to use during IM injection, ventro or dorsogluteal site?

Thanks alot and god bless you!!
My personal preferences are the deltoid muscle and the upper/outer third of the thigh. Easily found (especially in PACU, where posterior sites are difficult to access), no bony landmarks to find in an obese patient, and no history of nerve damage in either site.