There is no doubt that your marks in your Class XIIth examinations are quite less, however, this does not anyhow mean that you will not be able to perform well in National Eligibility cum Entrance Test or NEET. You have to work very hard but it is achievable and many people do it. Some of the points are:

• Work towards some very easy parts like Biomolecules, Polymers, Kinematic etc which are sure to come and have 0 chance of getting wrong.
• Give tests sincerely and analyse properly.
• Maintaining pace and not getting sad on few bad performances.

If you follow these steps, you are bound to perform well.

Hope I have answered your question. All the best!