I’m trying to decide between PRP and Juvederm around my mouth, chin and nasalolabial folds and Restylane under my eyes.

It is very difficult to answer your question without more information.  However, when in doubt I always fall back on science.  We have a great deal of information about injectable fillers and their benefits and limitations.  PRP for facial rejuvenation is very interesting but much remains that we need to learn about PRP.  PRP may offer some benefits but does not take the place of injectable fillers at this time. 

This is difficult to answer without photos. Fillers can be used to improve the appearance of folds and to provide support for the face. Under eye bags can be permanently corrected with surgery or temporarily camouflaged with fillers. I hope this helps. 

Without photos and the benefit of physical exam- impossible to answer your questions accurately. Generally speaking, sagging neck, jowls, cheeks are usually treated with facelift, neck lift . It's the most permanent solution and most reliable. If you are candidate for the above mentioned procedures, fillers and other non surgical procedures, in my opinion are useless if performed as a substitute for surgery.