dotted line on laptop screen

Solution
LCDs have connectors along two edges which allow the electronics to address a row or column (and thus every individual pixel). It looks like you've messed up the connection for your bottom row.

If you used some sort of liquid to clean it, you're going to have to open it up and let it air out until the liquid evaporates (hopefully).

If you didn't use a liquid, you can try massaging the bottom edge (left or right edge depends on which side the connector is on) until hopefully the connector makes full contact again. You may still have to open it up to get your fingers around the bezel.
LCDs have connectors along two edges which allow the electronics to address a row or column (and thus every individual pixel). It looks like you've messed up the connection for your bottom row.

If you used some sort of liquid to clean it, you're going to have to open it up and let it air out until the liquid evaporates (hopefully).

If you didn't use a liquid, you can try massaging the bottom edge (left or right edge depends on which side the connector is on) until hopefully the connector makes full contact again. You may still have to open it up to get your fingers around the bezel.
 
Solution