Yes, I think you should. I am having trouble fitting the image of what you describe with anything I've ever seen, unless of course these ARE scratches. The only conditions I am familar with which produce long lines are 1)jellyfish stings and 2) dermographism, or hives from histamine release when the skin is rubbed with a sharp object, whether a fingernail or something else.
I would therefore consult a doctor as soon as you can arrange it. Perhpas he or she will see something I can't picture, or perform a relevant test to see what's going on.
Best.
Dr. Rockoff