I Have A 16 Year Old Son With Very Well

I have a 16 year old son with very well controlled cystic fibrosis GE had had no need for treatment and had little or no problem since an emergency disimpaction at age 4. Approximately 3 this afternoon while on the bus he suddenly got burning sensation in mouth and stomach got pale and said felt like his stomach was burning like going to explode. Once he got home He made himself vomit which was white and red and the consistency of molasses. This eased the pain temporarily now the burning is back. He went to the bathroom which was normal except he said it made his rectum burn also. ( he says it feels like he drank hot sauce but he didn't ) do I need to get him to a hospital?