What a cute little betta you have!
My betta has often looked a bit bloated like that as well, and since getting constipated can cause health problems I would recommend fasting him for day or two until you see him poop.
Just to make sure he is digesting correctly! He doesn't look too stuffed but its always good to clean out the system once in a while..
You can always try the pea method as well, i've never used it but apparently it works wonders. Just peal a pea and feed a little to your betta and it should clean out his digestive system. (others can correct me on that) Or you can boost the heat a little bit, that should also help him digest as well. Oh! and of course you can make him flare for like 5-10 minutes, that's a third option!
What I do, and i dont know if this works on fish the same way as humans(prob not), but I make him chase my finger around for a good ten minutes a couple times a day.. so the more he "exercises" then he can work off what he ate! But, that's probably more for my entertainment than his. ahaha :D
Anyway, he doesn't look too bad but fast him for 1-3 days to help him out! Just feed him when you think hes gotten rid of the excess food :)