Each House may determine the Rules of its Proceedings, punish its Members for disorderly Behaviour and, with the Concurrence of two thirds, expel a Member. -- U.S. Constitution (Article I, Section 5, Clause 2)
(Which is a laughable statement in and of itself, given how much Congress violates the Constitution on a daily basis.)
If Massie were in front of me, I'd ask these questions:
1) Is levying a fine somehow beyond the scope of punishing Members for disorderly behaviour?
2) What definition of "excessive" are you using vis-a-vis the 8th Amendment with regards to the fine?
3) Would this hypothetical censure and fine of Schiff be considered a "law varying the compensation for the services of the Senators and Representatives" vis-a-vis the 27th Amendment?