An increase in the marks while rechecking happens rarely. You get additional marks either if an answer has been left unchecked or if there is some calculation mistake in marks. Otherwise, you don't usually get an increase in marks after rechecking. While rechecking examiners don't usually see if you have rightly got 1 mark in a 5 marks question.

Another option to gain marks is to fill out the challenge form. But the challenge fees and rechecking fees are high (INR 7000 and INR 1000 respectively). You can also opt for carryover paper. For this, you will have to work hard.