Re: Blood Vessels In Foot
I am not a doctor and you haven't posted a photo of your foot, but as a former Boy Scout my bet is blood blister. Search online for proper treatment of blisters. This WebMD link (since WebMD is a partner of HealthBoards) talks about how to treat smaller blisters.
If you have a blister and it does not appear to start healing on its own within 4 days, or if it gets infected, then you should see a doctor.