Problem: Hey Usher, Big Girls Need Lovin' Too!!!

Usher needs to lighten up by doing the opposite of lightening up -- he needs to start dating big girls ... at least that how Problem sees it.

We got Problem Wednesday at LAX and he had a clear point of view -- Usher should not turn his back on babes who got back. As we reported, Usher claims he never slept with the woman who is suing him for allegedly exposing her to herpes ... the one who appeared at a news conference with attorney Lisa Bloom.

But as quickly as Problem admonished Usher, he trashed-talked big women, saying their chances increase the later it gets.