got a long hair piss boy

So I had a guinea pig dropped off today because his owner couldn't keep him and it's been about two hours and his whole ass is soaked in pee because his fur is so long. Should I just wipe his butt and tummy with a warm damp cloth or would it be okay for me to take him in to a groomer and get him trimmed up a bit cause the dude is a piss freak and every time I look at him I loose my shit laughing but it can't be good for him lol

Edit: please stop telling me how to do it myself, he's a brand new addition who doesn't even let me pet him. My other guinea pigs took a minimum of a month to start warming up, I just wanted to know if it was safe to get his hair cut since he's the first long hair guinea pig that I've had for an extended time/permanently