Bleeding at the Injection Site
It's normal for a small amount of blood to appear when you inject insulin. This bleeding, which is usually caused when the syringe punctures a tiny blood vessel, can be stopped by putting pressure on the injection site with your finger or a cotton ball.
Also, be sure that you:
Don't rub the spot.
Maintain light pressure with your finger to prevent bruising.
If a bruise does appear, don't use that injection site again until the bruise is gone.
If you frequently bleed when you inject, you're probably injecting incorrectly, or you may have a medical problem. Consult your healthcare professional if you find that you're bleeding frequently.