taking my second dose of T

so I’m about to take my second dose of testosterone and I am wondering about how to go about it because I did it wrong the first time so I just kind of wanna be prepared. I called my doctor about it already and they said it was fine, but I just wanna get a second opinion just in case I have a 23 gauge and 25mm needle and I am about 90 pounds so my legs are pretty thin not super thin but thin to where im concerned about pushing it too far. My doctor told me I have to inject it all the way, but I’m wondering if I should pinch my skin or not pinch my skin that’s the only thing I’m asking so I don’t go too far into my muscle so I’m just wondering whether or not I should pinch my skin or just hold it like flatten it out or just do nothing and push the needle through, doing intermuscular injections by the way