a small reddish bruising about the size of a pencil erazer head keeps coming up on my left top four arm and sometimes it can come up on my right arm but always on the top forearm i haven t hit it on anything or been bitten by anything they have been coming to the top of skin for about 5 months will pop up out of nowhere and then slowly go away about 4 days later but just to come back to the top of skin in the same area sundenly days later either left top forearm or right top forearm and today i noticed it was a a little sore and also a little lump when it appeared this morning worried please help