Your baby is adorable.. 
Please let us know what the culture comes back with.. It sounds like the problem is his mouth so I hope thats where the culture was from. Just curious, what type of anitobiotics/meds did he give you? My Mikey was sick last year and he couldn't eat either and got very skinny.. He too had a infection in his mouth so it was painful for him to eat. I was able to get him to eat oatmeal & would mash up sweet potatoes w/rice, he liked that too.. They started him on Doxycyline but unfortunately it took a few cultures to get a *exact* diagnosis.. In the end, Mikey had mrsa and had to be put on Amikacin. And Mikey is just fine now.. 
I hope you get a quick definitive diagnosis.. 
Please keep us posted on those culture results.. We care.. Mikey and me are keeping your baby in my prayers..
Please let us know what the culture comes back with.. It sounds like the problem is his mouth so I hope thats where the culture was from. Just curious, what type of anitobiotics/meds did he give you? My Mikey was sick last year and he couldn't eat either and got very skinny.. He too had a infection in his mouth so it was painful for him to eat. I was able to get him to eat oatmeal & would mash up sweet potatoes w/rice, he liked that too.. They started him on Doxycyline but unfortunately it took a few cultures to get a *exact* diagnosis.. In the end, Mikey had mrsa and had to be put on Amikacin. And Mikey is just fine now.. I hope you get a quick definitive diagnosis.. Please keep us posted on those culture results.. We care.. Mikey and me are keeping your baby in my prayers.. 
