I agree with the above poster. It sounds like your ball python is hissing at you. It's something babies do and you should handle them anyway. They will hiss for a few minutes then settle down. My female spider did that to me for weeks until she finally grew out of it.
However, if it does happen to be the start of a RI, just keep an eye on it. If you start to see mucus or bubbles from the mouth, take the snake to the vet ASAP.