Hello

In university exams , forgetting to write your name on the answer sheet can sometimes lead to issues but since you’ve written your roll number, signed the sheet and the examiner has signed it as well it should be relatively easy for the examiner to identify your answer sheet based on your roll number. The signature from the examiner further ensures that your sheet is properly acknowledged.

However, it’s always a good to inform your exam invigilators or the concerned authorities about the oversight. If necessary, they may allow you to provide your name afterward or make a note of the issue. Generally your roll number is mentioned clearly, there shouldn't be a significant problem.

Hope this gives you the clarity you need.