Dear aspirant !

Hope you are doing well !

Definitely if you missed your 1 practical it will affect your marksheet. To be very honest ,I would say that it depends on school to school and your relation with the school teachers and principal. If everything is good then no problem will be there otherwise if you have some misunderstanding with the teachers they will show some rudeness to you that you will face in the result . You may request them for the same or do something under the table .

Hope it helps you !

Thanking you