I'm afraid that I must disagree with some of your posting. In high school, at least mine, if you miss more than 15 minutes of class you are counted as absent. I try really hard not to keep kids in the clinic for long because of that rule. If the student came to me and said that they were ok to return to class, I take them at their word, and send them back to wait for parent arrival there. When the parent arrives, I always talk to them about getting an MD order for the student to have their med at school, and provide the parent with one to take to the MD. More often than not, the order does not get filled out, because the parent prefers to bring the meds.
Now if the child is doubled over, I will let them lie down for a few minutes. We do not have heating pads, due to the risk of potential burning.
I had awful cramps too as a teenager, but I had to suck it up. My parents were unable to come for me unless it was emergent. My mom did not consider cramps to be emergent, but something that we had to learn to deal with, and deal with it I did.