http://i5.photobucket.com/albums/y162/xsafetypinzx/Photoon2010-09-01at1649.jpg

these marks showed up randomly on my chin this morning. i have no clue what they're from or how they got there, but they're sore to the touch and are dark purple in color. i used to get these when i was younger, in my teens, and they'd go away in a few days.  I've never gotten a diagnosis or reason as to why they show up every now and then.
I do not take advil, but i do have anemia... could this be a factor? they're perfectly semetrical, and i don't believe that it's anything i have done, since they've shown up overnight.

should i be concerned? should i see a doctor? what are these stupid 'bruises'?