Injections and implants (fairly new) are the most effective with least amount of possible detrimental health side effects as it doesn't go through what I believe is called second pass through the liver.
Sublingual from what understand is taking the same pill but holding it under your tongue until it dissolves, as far as patches are , they are hit and miss with the sometimes not wanting to stick they are however more safer than pills but are controversial effective, some like then some do not, and there cost is the highest per dose of the 3.
Long term health injections or implants are the way to go, however the implant route is much higher, I might suggest injecting in a different spot, like the bum as there is less chance of bruising there, it's where I inject mine, kinda a pain to do it there yourself but less likely of issues.
An extra thought from someone who has been on here for a bit, if I knew then what I know now I'd have been on injections long ago, much better bang for the buck and by far had my heart better results after I got on injections, of course I had grs/srs before injections but after the surgery I was still on pills, and it seems like I was just well maintaining what I had, but when I went to the injections....... Wow I started a growth spurt and have had more changes then had in a few years. And I've tried all 3 options, since your 18 you will most likely have amazing results.
