Tonight I had a session with my boyfriend and right after I noticed that I was really swollen. This has never happened before... and I have no clue why. I am completely clean (No STDs) and only 20 years old. I don't know if prolapses occur this young.. Around the opening of my vagina there is a "ring" of swollen... ness... and its quite uncomfortable. I'm not allergic to latex.. no condom was used. What is it?
... Worried.

So I put two and two together and found out that the cream (hydracortizone to relief ichiness) he rubbed on my side was still on his fingers during foreplay... Whooops! But could this be why?

Can't tell you whether you had an allergic reaction for sure... hydrocortisone can be used to treat vaginal irritation and can be used internally in other preps such as preparation H for relieving hemorrhoid pain, so it is used in that area and used internally in certain cases... but there might be something different in the topical cream that could have irritated you internally, just as a topical skin lotion can cause irritation internally if used as a lubricant.

Now, tissues around the outer third of the vagina and around the vulva do swell naturally during sex. Blood engorges tissues, much like the mans tissue is filled, and it produces a natural "cuff" that tightens around the man, giving friction. So... I'm not sure if you were more swollen than normal, whether it was noticed because of skin irritation, or whether you were irritated and more swollen...

Anyway, perhaps you have your answer. A topical ointment shouldn't be introduced internally, and it makes for a logical explanation. Until it happens again, that seems to be a reasonable answer.