If you have written but forgotten to bubble the circles in Karnataka Common Entrance Test or KCET, your first step should be to immediately contact the examination authorities and tell them about this scenario. They will then manually verify the written code by you and will fill the details into the system manually and your candidature will not be rejected.

I understand this may be a time of uncertainties for you, but this will pass and you will easily get you deserved rank in the examination.

Hope I have answered your question. All the best!