Hello! Yes this is a real drug with the chemical name desomorphine which is a synthetic (designer) morphine analogue. It was originally studied as a morphine alternative in the 1930s in the US.
It was dropped due to problem with controlling the dosage.
The problem with people using it at home is that it is often impure and has all kinds of nasty additives that cause severe tissue damage. It does not make people into zombies as some suggest but it can cause much more tissue damage then most drugs that are injected such as meth, heroin, etc. If it not a common drug of abuse and not redily available. The photos shown on the site you provided are interesting but not actually what happens with users of the drug in most cases. tissue is severely damaged from injecting impure doses of the drug and the drug itself is damaging but will not cause the extent of damage you see or make the person crave flesh.
Thanks for your answer.
You are very welcome! Thanks for your question!