That is certainly some bruising. Probably couldnt find a decent vein and had to probe around a bit so causing all the subsequent bruising. This happens quite frequently. It looks Ok and will fade eventually so dont worry. If bruising should break out in another entirely different place then see your doctor, but I doubt that it will.
Looking at your pic you have deep seated veins so if you need to give some blood or have a cannula again, try to have a glass of water beforehand and be well hydrated. It makes it easier