Everything I just typed disappeared....argh...okay, sum up;
Cats get over abcesses usually on their own, but by monday if it's not draining or very angry/red or causing pain (they usually don't), do take him to a vet.
You can use a hot compress - soak a towel in hot water (and epsom salts if you have it) or a heating pad and hold it on the spot (if the cat will let you) and if it starts draining, press a warm damp towel near it to help it drain (if the cat will let you. not a pain issue, just a "Cat doesn't like being poked and prodded issue!" :) ) Dont' worry if it closes over and re-drains, it may sprout more than one drainage hole, this is normal. For the most part, these infections take care of themselves and the cats never seem to be in pain from it. However, if it is near a "sensitive spot" down there, it may make the cat a little more uncomfortable than these things usually do and you might want to get it taken care of if it doesn't resolve itself quickly.
in and heal on their own quite well
Thank you ,
They can get him in late Monday I will try compresses and see if i can get it to drain. If it is not better by mon I will take him . I don't think it bothers him unless it is touched . He is sleeping a bit more , other then that he is acting fine (as long as you leave his back end alone )