I would not recommend going over your professor's head at this point. At least, it is not clear that you have done everything possible to turn the situation around. I'm hoping that your goal is to understand the content of the class so that you are not wasting the term.
I think that, instead of asking the professor to change, you should approach him under the premise that you want to adapt to do better in the course. To do this, I would propose the following strategy:
1) You want to understand the grading of the homework. So go to your professors office each week with your graded homework and tell him/her you want to find strategies for doing better on future assignments. Ask to go over the assignment to learn how/why you lost points.
DO NOT ASK FOR POINTS BACK. If the grading is fair, you will get a better sense for what is expected. If it is not fair, s/he will likely recognize this as you go through the assignment, and might offer to regrade it without prompting. Be polite and engaged with the material. You want your professor to take an active interest in your success in the class.
2) The midterm may or may not have anything to do with the content of the course. At the master's level you should be expected to go beyond regurgitation and apply your knowledge. Take your graded exam to your professor and tell him/her you want to learn the material better. If you do not understand how a particular problem is connected to the course, it is okay to say so. But, don't make it seem like it is the professor's problem. Remember, you are trying to learn. You might say something like "could you explain how you think about this problem? I didn't see how to solve it using the techniques from class."
Again, DO NOT ASK FOR POINTS BACK. Give your professor the opportunity to help you understand the test. If some aspect of the test is unfair, allow your professor to realize this on his/her own. As before, be positive and engaged. You do not want your professor to feel threatened.
In summary, I'd like to remind you that professors are people too. If you only give negative feedback, you are unlikely to get the outcome you want. If you are not receiving the support in class to succeed, it is okay to get more help outside of class. However, this is going to also require more work on your part.
It is going to create more work for your professor as well. If other students struggling in the class do the same thing, this will amount to a lot more work, and may be enough incentive for the professor to make the changes you are looking for. Just make sure you keep your interactions polite and respectful.
If, in the end, this strategy doesn't work, you will have taken concrete steps to improve the situation. This will be important if you ultimately feel you need to take the issue to the department chair.