as for the needles , dont worry too much. i suffered from neoropathy, not the kind where go eventually go numb, but the rarer one where every thing hurts much mor then i go numb. So the needloe thing was way worse then it really should have been, and that is why ai needed the find different areas of injection.
If you can pinch fat on your theigh, you shoud be able to use that spot well enough. just as whoever it is that is training you on the injections.
AND QUIT BEING A WORRY WORT, OR I WILL START BUGGING YOU ABOUT IT! ha!