Oral sex from a women caused a sellling of my penis

[Tiomio]

A few days ago I had oral sex from a woman I met in a bar.  an hour later I noticed that my penis was red and puffy below the head.  There are areas where it is puffy and bumpy,.  No sores or pimples.  I do not have any pain or unusual sensation - but it scares me!!  I am married and worried that I may have gotten an STD.  I remember years ago when I was single that sometimes after a lot of intercourse I had some swelling and redness, but I think it went away in a day or two.  This seemed to get worse over night.
I put some hydrocortosone on it a few times but do not notice any change.  I am very scared!!

[Tiomio]

PS to my posting.  I have been taking 20 mg of prednisone last 2 days. (20 each day) and putting cortisone 2.5 on the rash.  Today I awoke with both my arms with red rashes from weist to elbow.  I put on some cortosone and tonight my arms are clear and my penis doesn't look as red or swollen BUT now there is a deep rash on m skin where my pubic hair is.  

Can anyone with medical experience give me some idea if this seems like and STD, or maybe an allergy to the cream or oil that lady was using,.....  This can ruin my life as I have been married 40 years and I'm so angry at myself for doing it.....