Saline would go away too quickly. It wouldn't cause bloating, either. It is, after all, saline. Maybe a bit of inflammation at the injection point.
Better choices would be MCT oil.
Spot injections are stand up and parcel of the bodybuilding world.http://www.spotinjections.com/index3.htm
Not as invasive as a nose job, nor an implant, and not as bad as botox, but, not without risk, nor pain, either. A cosmetic procedure, like many things, but, with more long term results.
It works because the fluid enlarges the fascia and the muscle grows into it, giving PERMANENT gains.
Used properly, the neophyte never spots it. When abused, like food, implants, plastic surgery, or even botox, the results can look like crap. (E.g. Greg Valentino)
This has been around for many years, albeit a bit undercover. It's commonly called "Pump and Pose."
The guy in the video above is not very smart. He's asking for trouble as he is ignoring sterile procedure.