strange lines on model

i’m new to blender/3d modelling and doing my first project now. i’m trying to model my head, however i’m not familiar to blender’s options and so on.
you can see in the picture below that there are those black lines on my model… it might be a very stupid problem, but can you help me getting out those lines anyway :smiley: ?


Select all the vertices and recalculate the normals.


thank you :), now it looks better