A Week Or Two Ago My Friend Dared Me To

A week or two ago my friend dared me to eat a piece of green chalk and long story short i ate it the piece was not even as big as a dime but this week for the past four days i have had terrible stomach pains below my belly button and have been to the doctor and they gave me laxative to flush out my system. I never told the doctor i ate the chalk. Any suggestions