1st, Thing for me was just spar alot
2nd, Thing its a normal reaction to close your eyes when something is thrown at you. How to work on that?
Stand with your back against a wall and tell a training partner to slowly start throwing punches at you and just focus on keeping your eyes open and guard up. When your getting comfortable start increasing speed and power.
A funny "trick" that can also work is that you take a bucket fill it with water look down on it and start splashing it towards your face, the normal reaction is to close your eyes so try to keep them open, might help with the flinching reaction.
ps. english is not my native language, dont be harsh on me : )