If you’re skipping, own it. A fake excuse turns a small choice into a lie.

Skipping something is a decision with a known cost: a mark in a register, a conversation, somebody disappointed. Inventing an illness swaps that for a story that has to be maintained, and the person you told has been handled rather than told. The excuse is what converts a small decision into something you then have to keep track of.

If you are not going, say you are not going, and accept whatever the ordinary consequence is. You do not owe anyone a diagnosis. People forgive an honest absence far more easily than an invented story.