-Clean the whole bowl out. Feeder tabs are notorious for polluting the water. Even without the feeder tab, you should be cleaning the bowl at least every 2 days to keep the ammonia at safe levels.
-Feed him some daphnia, or, if you can't find any, half a thawed, deshelled frozen pea. Those blocks could have bloated him.
-Keep him warm. Since your betta is in such a small container, you will need to heat your whole room in order to do this. There are simply no heaters on the market that can heat a bowl without cooking it. You are aiming for 78-80 degrees. Buy a thermometer if you have to.
Okay I hope this helps you! I'm sure he'll be alright in no time :)
In the mean time, you should check out this link http://www.fishforum.com/betta-fish-...are-faq-20058/
to find out how to set up a lower-maintenace tank.