4 month old refusing to eat food

So before you judge me, my 4 month old is the length of an 8 month old and the weight of a 6+ month old 
He liked baby food and baby oatmeal when I first gave it to him 
Now he refuses both???? Why?
SOMETIMES he will eat the applesauce 
But other than that he spits everything out and makes icky faces lol