LCD screen gets hot and sucks power from Raspberry Pi
It's hard to tell from your description (well-focused, properly cropped, well-lit photos would help) but ...

The "black dots on the back" are probably "Chip on board" (COB) packaging of an LCD controller IC. If that's heating up to near 100C ("boiling), you certainly have problems and are at or beyond the point of permanent damage.


Photo©MikroLogika

Photo©RedGrittyBrick

As I said in a comment, my best guess (and it's a guess because there is insufficient information for anyone to know the answer) is


You haven't wired up your circuit correctly and/or
The diagram you are following is incorrect and/or
Your module isn't like the one in the tutorial you are following.




These type of LCD module come in 3.3V and 5V variants. The tutorial you are following is  drawing power from the Pi's 5V pin and is for a 5V module. Maybe your LCD module is a 3.3V variant. In which case it should not be connected to the Pi's 5V power pin.

Note: "The maximum permitted current draw from the [Raspberry Pi's] 3.3 V pin is 50 mA."

If you look at a datasheet for an example 3.3V LCD module you'll see that it claims a supply current (IDD) of 2.5 milliamps, the backlight current (ILED) is 19 millamps (mA) So if you are measuring over 1000 mA (1 A) - something is very very wrong.