I have recently had a freezing cold, swollen, numb but painful to touch, paralyzed, bruised coloured wrist with no injury, what could cause this?

Blocked artery/vein: There are a few possibilities here. Has the problem resolved? if so you may have had a problem with vasospasm, which can happen with use of Sumatriptan, or can be due to another issue. If this is still ongoing, you need emergency assessment, as damage to your hand could be serious. Occasionally nerve dysfunction, RSD or improper positioning or compression can be cause. You need to see a Dr. ASAP.

EMERGENCY: Signs of lack of blood getting to the tissues of an arm or a leg include numbness, paralysis, coldness, blue color. These are signs to go to emergency room IMMEDIATELY. If there is a blockage in an artery, measures can be taken to restore circulation and save the affected limb. Certain meds (eg sumatriptan) constrict arteries, although I've not heard of this particular symptom with sumatriptan.

Bruised wrist: You may be any to get your bloods done and see a GP. Make sure that the brushing is not related to platelet deficiency or any blood disorder. It will be hard to comment for me more than this without proper history.