Help with guinea pig constipation

Ok. Max my male guinea pig has been since last wednesday. He still isn't eating or drinking so we have to force feed him mashed up pellets and baby pablum. We have tried water but he keeps spitting it out :| He won't eat anything but grass on his own. He has hardly ant turds in his cage and he has poop stuck in his bum. I have been trying to get it out the best I can but his butt is tore a little and all chaped. What can I try?

 

Max needs to go back to the vet. He definetly has a blockage from what you've been describing. He'll very likely die without some sort of help.