yeah, once he saw it, he doesn't need a warrant. assumes you are in usa... you allowed him into your home and anything in "plain view" does not require a warrant or whatever etc. you are probably fine but being a little paranoid isn't a bad thing. if possible, a temporary home plants and drug utensils wouldn't hurt.
though i guess a lawyer may be needed sicne he actually opened a door... i think he knew what was behind it before he opened it and was screwing with you.
if you sell dope, i'd think real hard before continueing to do so from your home... they watch and they watch and they watch some more... knew a lady that had a family curfuffle that made her quit growing (you can fill in blanks any which way), and when she started up again 6-12 months later they busted her. they were watching or at least keeping tabs...