dear spandan
first of all donot worry , keep mind cool .
you need to do the following things in these 3 months .
1- take last 10-15 years of neet and aiims ques paper practice that chapterwise .
2- note down the topics where u did mistakes from the papers
3- go through ncert for that perticular topics .
4- and then again attend any mock test or full test avaliable online .
5- and also every month u need to give a full test on neet level .
6- revise every 5 days whatever u studied .
HOPE IT CLEARS
REGARDS