Depends on the type of visit, and for some having weapons on you is contra-indicated.
If just a regular Dr visit, this is very much a NPE area which requires covert carry, not just concealed carry. Different guns, different holsters, different concealment positions may be required.
You absolutely do not want to get made and thus jeopardize your ability to be a client there.
What about a dentist visit? Lying back in the chair presents challenges, too, such as cover garments riding up or coming open. How about a pocket gun falling out, or being noticed when the pocket opening flares open and that dentist person is sitting there real close to you.
Again, these are COVERT carry situations, not concealed.
You also absolutely cannot a mishap: gun falls out of the clothing, ND, forget the gun, etc., all of which have happened. Even to “professionals”.
Leaving it in the car unsecured is dumb dumb dumb. If you have to, then a lockbox, but it better be hard for a bad guy to rip the box of the tether or mount, or it’s just the illusion of security.
Bring a backpack, preferably one of those non MIL/LE looking ones with the secret pistol compartment that is between two sheets of stiff foam. Have pocket litter type stuff in the backpack to sell it should you need to.
When it’s time to disrobe, put the holstered pistol, etc in the backpack. The pistol stays in the holster 100% of the time. Unnecessary holstering/unholstering contibutes to to negative outcomes.
If you need a more secure area to jock up/down, do so in one of the family restrooms that you can be the sole occupant of, and lock. This also works for jocking up/down at the airport or other such areas.
BTW, how many people know how to control their pistol when using a shitter? Several ways to do this that are better than others, and you have to know them if you are going to live the armed lifestyle.