Well, of course, you can wash your face after the surgery, only if you can make sure your eyes can not be moistened by the water. All we known that, after the surgery, your eyes will be very sensitive and fragile. So you should avoid getting water into your eyes, for your eyes will be infected easily by the viruses. So just be careful about it. Also, you should avoid eye injuries by wearing a protective eye patch. Also, you should remember not sleep on the side of the operated eye for the first night. By the way, some heavy exercises should be avoided.
Anyway, you should know there will be some side effects of the surgery, that is , you will be required not to touch water until they take the stiches out, that would take you about 8 days or so, just try to be careful. Anyway, you could try to gently wipe your face with a wet towel, but be careful.
No, you'd better not wash your face after the blepharoplasty because of the maybe infection from the water. As we know, there is a lot of invisible bacterium in the water. Washing the face may affect your recovery after the blepharoplast. You'd better wait for a week basic recovery and then you could wash the eyes with hot water.