My left nipple is bigger than the right one. Is there anything wrong in it?

Hi. I presume you mean areola (the pigmented part around the nipple) - 7 out of 8 women have minor differences between their breasts in terms
of nipple position/volume/position of the crease under the breasts, so this is normal. If you look at some of the photos on the link below you will see how different people's breasts can be. If it bothers you the difference can be corrected. There are trade-offs however - you have permanent scars around your
areola. Regards Dr Charles Cope