If you have a skin infection, will you most likely get a fever?

Not necessarily. A person can get a localized skin infection of significant importance without running any fever. Those with abscesses often never run a fever even if it is large.

It depends. Superficial fungal infections like ringworm or jock itch do not cause fever, Bacterial infections like cellulitis do. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV and Covid vaccines. Wish you good health!