If you want to treat a skin infection go see a doctor, get some antibiotics and take them for the FULL course.
I don't think anyone doubts there may well be uses for cannabinoids in doses over what the body itself produces.
It's stuff like the inference that cancer is a modern thing so must be related to societal changes, or the nonsense conspiracy stuff that's really quite annoying. Everyone's entitled to their own opinions, however it's largely demonstrably false.
For example the whole cancer being a modern illness stuff. There have been remains found predating modern society that show tumors in the bones from metastatic cancer.
On top of what Jolfa said about increased life expectancy, increased screening and diagnosis is inflating those incidence numbers.
If we lived long enough we'd all get cancer in the end, it's simply the consequence of disorder from increasing entropy.