Is there anyway to make cracks (small ones)in a iPhone 6 Plus go away or be less noticeable?

Is there anyway to make cracks (small ones)in a iPhone 6 Plus go away or be less noticeable?

Yes, by replacing the part of the phone that is cracked.

So if the screen is cracked, replace the screen. If the housing is cracked, replace the housing or put a case on the phone.