Is there any possibility to thin my knuckles...? since last 8 to 9 years l cracked my fingers knuckles and it makes me so embarrassing that my hands looks like too weird..?

Unlikely: Cracking your knuckles did not make those bigger. I understand it is a cosmetic issue for you, but it is not a disease. Have a healthy diet, exercise 30 minutes/day, drink plenty of water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/. Get HPV and Covid vaccines. Wish you good health!