Is it permissible to wet one’s eyes/eyelids (with water) [with one’s fingers] on Yom Kippur (Kol Nidrei) night in order to remain awake? If not, any suggestions to refrain from sleeping?
No, even dipping one’s finger in a tiny amount of water is prohibited on Yom Kippur. Only to remove dirt is using water permitted.
Smelling cloves or other fragrant spices help some people stay awake. Stepping out of shul and walking around may help as well.
Many mistakenly overeat on erev Yom Kippur which causes fatigue at night and does not make the fast any easier.
see Shulchan Aruch O:C 713:1