I agree with other comments that you should definitely share these criticisms with the department head. If you're concerned about wording it well, so you can document times more accurately and so it doesn't sound like a grudge, you may want to write up your letter ahead of time, type it out, and slip it into the folder with evaluations. [Assuming your school does like mine where the professor leaves the room during evaluations and a student hands it in so it can't be tampered with. If your professor will be in the room, you may not want him/her to see you turning in a printed page -- might get the wrong idea. But you can still give it to the department head separately, particularly if you do want to use it to lobby for a free replacement class or other compensation.]
no subject
If you're concerned about wording it well, so you can document times more accurately and so it doesn't sound like a grudge, you may want to write up your letter ahead of time, type it out, and slip it into the folder with evaluations.
[Assuming your school does like mine where the professor leaves the room during evaluations and a student hands it in so it can't be tampered with. If your professor will be in the room, you may not want him/her to see you turning in a printed page -- might get the wrong idea. But you can still give it to the department head separately, particularly if you do want to use it to lobby for a free replacement class or other compensation.]