I had protected sex with a girl, could i get visible genital warts on my testicle skin just after 4 days of exposure???

It will take weeks for an exposure to genital warts to pass that condition to you. Anything you see coming up at 4 days is not genital warts from that exposure but could be from another exposure earlier. What you consider "protected" sex may not be very protective since these come up on areas not blocked by condoms.

It takes 6weeks or more to get visible warts after exposure. In this scenario chance of getting warts is very low