Burping a baby

Brianna • TTC my Rainbow Baby ! Miscarriage 12/26/14 & Ectopic with Left tube removed 5/20/18😇😇
Ladies i have my month old Baby Brother for the day .. He ate 2 and a half ounces around 9am burped him after he drank half .. And I was trying to get him to burp again when he was all done with the bottle for like 45mins but he never did and now he's in a deep sleep .. Should I be worried that he will throw up ? Or is he fine. . wouldn't he have done it already