I am pretty new to blender. I am trying to model a mask from a video game, and while I am trying to smooth the eye area, these “spikes” keep popping up. Im not sure what to do. I had made the mask from a UV sphere , booleaned out from a face model. Any help would be appreaciated. I've tried shading smooth, solidify modifier, and nothing has seemed to work. This is the file: https://drive.google.com/file/d/1HaHhav8OdKQ6mFUZqk-QrsdmxBG-qKhI/view?usp=sharing
The reason you get artefacts with smoothing is that you "Booleaned" two objects of different mesh density. The front of your mask is too dense and the back of the mask is low poly. The spikes caused by smoothing will be exactly at the border between the two densities.
What you can do is remesh the mask to desirable density using the Remesh Modifier or in Sculpt mode enable Dyntopo with Detailing = Constant Detail and Resolution ~= 130, then click Detail Flood Fill button.
Note: Enabling Wireframe overlay on your object will give you an idea about the mesh density in both cases.
Once you are happy with the result from the remeshing you can apply a Smooth Modifier or smooth out the surface via sculpting.