My Son Is 16 And Wrestles. Last Saturday I Packed

My son is 16 and wrestles. Last Saturday I packed him fiber bars instead of protein bars, he ate four of them. Since then he has had diarrhea and cramping. I took him to the walk in clinic on Wednesday, it is getting a bit better but still hurts, especially after practice. I have given him Keifer and yogurt and a bland diet. Will this go away or should I make him an appoint to be seen next week? He is not losing weight, no fever no blood in stool but he did have some mucus the other day. nothing since then