Is it okay to apply basic skincare products or sunscreen when going to the dermatology clinic?

I suddenly became curious about what my makeup should look like before visiting a dermatologist for a consultation or treatment.

I would like to know if I need to go for a consultation with a bare face so that my skin condition can be accurately assessed, or if it is okay to apply basic skincare products or sunscreen.

Please let me know if people usually wash their faces completely before going, or if they wash them at the hospital.