@atifaslam7 I didn't mention face at all; you don't use just the face to recognize someone, though the face is usually the most prominent. As I mentioned before, all he seemed to have done was take the mask off, so unless the mask obscures more then just the face, the stalker could have recognized him through: 1. Height, 2. Clothes/Equipment, 3. Build(aka body structure), 4. Cultivation, etc
Though, I guess the guy could just be that dumb, cuz he didn't even tail them properly, with how he followed them in basically plain sight, not bothering to hide. -- He didn't even suspect someone standing in the middle of the walk way. If the person was a customer, they'd be sitting or moving about.