Yes like the guys have said this is normal. Next time try aspirating first so this doesn't happen as often. However if you do aspirate there is still a chance it will happen. If you hit a vein and aspirate you'll know right away. If you hit a blood vessel you won't know till afterwards but it won't hurt a thing. If you do aspirate and draw up blood, immediately remove the pin and inject somewhere else...you don't want to inject oil into your veins at all.