strange bruises on my left armpit
I'm a 22 year old male in good health and noticed some pain yesterday in my left armpit, but I didn't think too much about it.
I woke up today to a bit more pain and discomfort. I lifted my arm at the mirror and noticed a bruise about 1/2 wide and 2 inches long on my armpit. I can't tell if there is any swelling in the area of the bruise.
The painful bruise is only on my left arm. I have no pain, discomfort, or bruising on my right.
I can't recall bumping it or leaning against anything that would have caused the bruise. The pain isn't unbearable, but it's certainly uncomfortable.
I did start using a new deodorant about three weeks ago--Sure Max, which claims to be dermatologist tested if that's worth anything. And sometimes I put it on, then later apply the normal deodorant that I have been using without incident for 10 years or so.
Is it possible that the new deodorant is causing this after three weeks? Should I seek medical help or at what point should I become more worried about this?