Weird lesion on a vessel on my arm, smooth to the touch and not painful

Just wanted to know if this worth worrying about/what it is, apologies in advance for bad photos. 17M, no history of skin conditions other than acne and some warts (none of them looked, felt, or popped up like this), appeared about a month ago, some minor swelling roughly a centimeter around the legion, appears to be filled with some kind of muck and some blood, not painful to the touch in any way.