Bro, if you're tunning prop 12 weeks, I highly suggest you get 25ga needles and rotate your inject sites.
glutes get 23ga 1.5in, quads and delts get 25ga 1in. Injecting in those 6 sites EOD means you do not hit the same site more than once per 12 days, thats VERY good.
Nicking or even going thru a vein is quite normal. Just be sure to aspirate to make sure you do not inject in the vein. With enough practice you'll get to feel when you're about to go thru a vein and avoid it. Nothing like ED or EOD shots to get lots of practice fast
Red