It is quite normal since the muscles are relaxed during sleep, the mucuos tends to leak through the rectum. I was told by my GI surgeon that the mucous formation in the rectum/J pouch is a healthy sign to show that all is well inside and the system is working. Do not worry too much.
In so far as pain is concerned, a little pain may not be an issue, but if the pain is unbearable, you must immediately get in touch with your ET or GI surgeon.
Keep us posted.
45 years Male Attorney
Diagnosed UC October 1989
Had two stage J Pouch Surgery Nov 2005 Take Down March 2006
Complications after surgery - Incisional Hernia and Ano Fistulas
"Faith is the bird that sings when the dawn is still dark."
"There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracl: Albert Einstein
"What you are aware of you are in control of; what you are not aware of is in control of you."