<p>My Ender 3 LCD display was working ok, I went to turn it on recently but is not showing any signal of life anymore...</p>
<p>I have tried unplugging and plugging again, is there a way to test if the screen still works?</p>
<p>What is the issue? Or should I just buy and install a new LCD?</p>

The fact that the bumps were in the same spots on multiple occasions points to z-axis problems. Turn your printer off and manually turn the z-axis all the way from bottom to top. If there are any tight spots, there is some
z-axis binding
. If there are no tight spots, skip to the last paragraph.
Try taking off the z-axis by removing the set screws (pictured below). Remember which side was pointing up for a later step.
Once you do that, clean the screw thoroughly with a brush, cloth, solution, or a combination of those. Put the screw back in the opposite way this time.
If you get no bumps, then it was indeed the z-axis
If the bumps are still there, try lowering your temperature some more(200 is still a little high compared to what I do for PLA), and
calibrate your e-steps
if you haven't already.