In your case there is can and should. Can you narrow the thumb, technically yes. Should you narrow the thumb in your case, no. Your thumb is normal. You don't like that your nail is wide and the tip of your thumb is shorter. The hand is a very interesting area for aesthetics. First and foremost it has to be functional. That is the issue for you. Making your thumb more narrow would give you problems with your joint and would also likely give you some nail abnormalities. This is unacceptable. There are things that you can do to make the thumb look less squat. Lose the black nail polish. It only draws attention to your nail. Use a beige or lighter pink polish. Allow the nail to grow a little longer and round the tip slightly. Keep your nails well-groomed and keep the polish fresh and not chipped. If you can't keep the polish looking fresh then don't polish.Now, Megan Fox is a very successful and beautiful woman. Clearly, it is possible to do great things despite your thumbs. When it comes to cosmetic body alterations you should never do this because people taunt you. It won't stop the taunting. Do cosmetic surgery because you don't like something, not because someone else doesn't like something. Thumb surgery isn't worth it and it won't give you what you want.