A good beginning! Sculpting gets easier and more fun with experience - and you will get a lot with this course.
Btw it looks like some parts (e.g., chin) is asymmetrical and I see you don’t have symmetry turned on. Unless that was your goal I would keep symmetry on for now as it is half the work 
As bOBaN said, some parts are asymmetrical.
Maybe start over again, with a blank sheet. Because it is better to have symmetry.
And you learn more by repeating the process. You are just at the beginning of the process.
Better to retry than have problems later in the process.
I think you are too eager to create the Orc.
It is not about creating an Orc but the process of sculpting.
And if the base is OK the rest is easier.
no I tried the symmetry option it does not really work for some reason
also I can fix the problem
and thanks for the suggestion!
You must use symmetry not half way a project, but at the start of sculpting.
But I must say, even I know the problem and symmetry is on.
Strange things can happen.
I see that mostly on the hands
Hands are difficult because of the faces inside, when making indents. Maybe then the geometry become more difficult for blender. Maybe because of dynotopo on?
I can’t say, but I had also difficulties in symmetry on the very detail levels of sculpting.
Maybe is the machine problem, low memory … I use a fairly simple laptop. Blender crashes a lot on texture painting, large bitmaps, particles (hair) material nodes (high calculation stuff).