Injecting insulin in non-conventional places?

My apologies if this has been asked before, but I didn't really know which words to use to search for it.

Because of lipohypertrophy and lipoatrophy on quite a lot of places due to not having been properly educated about lipos as a child, I often find myself struggling to find any places to inject because there aren't many left that haven't been overused, and I have become pretty afraid of making it even worse. This has made me think about trying to use different places that aren't recommended (stomach, upper outer legs, butt and upper outer arms). Examples for alternative places I have been thinking about are upper inner legs, lower inner legs, upper inner arms and hips as I have a some fat there as well that seems to be painless and easy to inject in. (Maybe even breasts for women would be possible? Not that I would ever try to do that as it seems painful, but theoretically it should be possible, no?)

I'm hesitant to try it, but why would doctors not recommend these or other places as long as there is enough fat present to be able to properly inject? Any thoughts or experiences with it?