Dear candidate, technically the proper degree that would help you to fulfill your dream of designing car exterior is Automobile Engineering but there are few colleges offering this degree across India. Now there is definitely another option which is Mechanical Engineering, you can still pursue your dream with that. Get detailed information about these two courses through the link

https://www.careers360.com/courses/automobile-engineering-course

There are different colleges teaching this course such as

IIT Madras

VIT Vellore

SRM, Chennai

PSG College Coimbatore etc.

Hope it helps !! Good luck !!