Protons are non-perturbative, indeed, but this does not mean that there are no virtual particles exchanged inside a proton. It seems like your comment implies that, sorry if I misunderstood.
On the contrary, this means that there are too many virtual particles (gluons) being exchanged inside a proton, so many that perturbation theory is not applicable.
On the contrary, this means that there are too many virtual particles (gluons) being exchanged inside a proton, so many that perturbation theory is not applicable.