Yuki-rat

Question
QUESTION: I am a first time rat owner of two boys, Yuki and Itachi.
I noticed that my usually very friendly Yuki-kun isn't quite himself.  (although he does seem to be eating and drinking just fine.)
He has always been very vocal about being held/touched/ect. but has still been very willing until today, when I went to clean the cage.
He was very upset about me picking him up and made several attempts for freedom, (which is very unlike him) then made a very loud horrible screech that I could only take to mean as pain.
Upon examination, his genital area seems slightly swollen and is tender to the touch, and his anus looks very odd. At that point he started wiggeling all over, trying to escape, so I scruffed him, hoping to get a better look.
He made a very loud hiss, than several more plus a screech, so I went to put him back, and my sweet loving wonderful rat bit me. Hard.
He has NEVER acted anything like this, nor has his brother (who does try the occasional soft nibble) Neither of them have ever been mishandled/abused in any way, so I can only guess that he was frightened and in pain.
He is now refusing to come out of his hut, or let his brother in, which is making Itachi very upset, because they are completely
inseperable.
I haven't changed anything in their cage/diet recently (other than giving them a pringle this morning) and I use the carefresh betting on them and the other pets.
I definitely want to take him to the vet, but as I probably won't get an appointment until Friday, I just want a second oppinion.
Please help, as both I and his brother are very confused and worried.

ANSWER:
Oh my....I just had someone write me last week concerning her male and his genital area etc....and it was 5 days later that she wrote me. The rat had no treatment and soon as I read her description I knew what was wrong.  I told her that without treatment he would die...and sadly just shortly after reading my response, she found him dead.  He was young, his age escapes me right now but he was definately under a year old.  

Do NOT scruff him any more, or any of your rats.  Although scruffing works for other species of animals, its not a good way to restrain a rat.

---------- FOLLOW-UP ----------

QUESTION: So what exactly do you think is wrong with him? Also what is the treatment, if there is one.
He's now refusing his little bit of my breakfast and he usally gobbles it right up.
Yeah, he's young. I got them right before Christmas when my gerbil died.

Answer
Please turn him over and check his genital area.  Is his penis sticking out and not covered beneath the sheathe  (extra  skin/like foreskin)  Are his testilces a different color?

I think he possbly may have a testicular abscess or some type of inection if it is swollen.
You really need to get him in to a vet today or you may  end up losing him. Rats health decline very rapidly and this has been going on for at least 24 hours. Its obvious he is in pain. It is pretty serious when a rat hisses, as this is a very rare occurence and only seen when the rat is in extreme pain or extreme anger.

Please let me know your location and I wll give you names  of  vets