I just found out a blackish red swelling (much like an insect bite) on my lower back just beside the spine. It itches a little, but it cannot be an insect bite since I was wearing warm clothes through out the day and noticed it when I removed my clothes. The same thing happened a month or so ago and went away after I took levocetrizine and applied some soframycine ointment. I want to know if this might be an indication of something serious.