Anyone know anything about hematomas?

So I got my blood drawn today on my arm and got a pretty decent sized hematoma. I get them very easily and this isn't the first time but this is definitely the worst. The hematoma was bigger than a golf ball and was spreading. I was given a pressure bandage and ice for an hour. I was then instructed to keep the pressure bandage on and put ice on it for 15 minutes every hour until bed. It occurred over 6 hours ago and almost my entire arm is still swollen. I'm worried, I don't know if this is normal or it's something I need to go to the hospital for? I'll attach a picture, it's my right arm.