Hello Ansh,

The issue you are facing about the photograph might not create a major issue, but I suggest you to get your Aadhar card updated to be on a safer side.

The authority can make a question about the issue as 4 years is a long time and you might have got some physical changes which might result in the mismatch, its not sure that this type of issue will rise.

But on the examination day you should not get involved in any sort of hassle and to avoid these hassles you should update the Aadhar card.

Hope this helps,

All the best !