Hiya...
Quite early in my teens I was put on the mini pill for really awful period pain (every month I would be doubled up, vomiting, for 3-4 days 😱 despite trying nurofen plus, the specific period pain pills, and various chunky prescription jobs!). This seemed to help ease things and i stayed on it for years, until married & we actively were trying to conceive. Until then, we'd been using condoms too (being belt & braces kinda people! 😛).
I think you just have to work out what will be best for you - if you already have to have a morning / evening injection at a fairly rigid time, then taking a pill at the same time won't be a big issue (well, it wasn't for me! 🙂)
Best of luck!