This is a common problem with students preparing for NEET. Watching videos is not preparing.
I, too, faced such problem in my NEET 2017 attempt. I knew each concept, had learned everything, but ended up scoring just 400 marks.
Watching NEET class videos is like watching a cricket match on TV. You can watch it endlessly, but it would not make you the next Sachin Tendulkar.
The step which most of the students miss out is PRACTICE.
You should practice at least 100–150 questions each day and clear your doubts on all the questions where you make mistakes. This doubt clearance part is essential.
By knowing the correct steps to solve the questions, you would be able to attempt them correctly the next time.