My Friend Claims She Had Fat from an Animal Injected into Her Butt - is That Possible?

using another patient's or animal's fat to be injected into your body is asking for problems. Do not do such procedcures out of a clean medical environment. These procedures should be done by doctors. If an infection occurs, such as mycobacterial, there can be weeks of treatment and permanent horrific scarring. There might be transmission of slow-virus infection that can produce severe systemic symptoms. This at home treatment should be reported to the local health department or nursing licensing board.

Fat transfer from an animal is not something that sounds legal and is not a sound principle. Given that it was done at a nurse's house sounds extremely fishy to me. That in itself is not legal unless she has established her house as a place to business and is certified to do these procedures.  To begin with RN's aren't supposed to inject fat in the first place. Fat from an animal will also be completely degraded by the body and any results are likely due to scarring.