Interesting take on a clicker-style game! I liked the cute graphics and simple mechanics. This would make a great mobile game!
As for improvements, adding sounds would really help. A simple background track and some audio feedback for when you successfully get the mask on someone. Another improvement would be to add some player choice to the mechanic. Right now you have to click everything but maybe you can add decoys that you're not supposed to click. Maybe you can also have "high-priority patients" which will make you lose instantly if you miss them, but the others just reduce your health by a smaller amount.
Hope you continue to polish the game, it has potential!