Good luck getting the potions through the FDA approvals process!!
All kidding aside, just ask yourself what happened to the people who once did any job that is now redundant. The jobs no longer exist, so anyone who might have done those things now does something else. Once enough potions come along, there will probably be a period of chaos within the health sector. Of course Big Pharma will probably react most harshly. Corporate Medicine will also react harshly and so will the insurance industry. These entities thrive and make their billions on the fact that people get sick and need treatments.
Ordinary nurses and even doctors will probably (deep in their hearts) feel an impending relief that people will no longer have to suffer illness or injury. But they'll also feel the stress of impending job loss (more so physicians).
In the US, about 20% of the GDP goes into healthcare; 10% of the population is working in healthcare. That's a huge blow to any economy. It's not just nurses and physicians either. It's hundreds of thousands of technicians, medical assistants, receptionists, engineers, housekeepers, nutritionists, cooks, caterers. And it's not just people that work in hospitals, it's companies that make medical supplies & equipment, it's technicians that keep that equipment working and truck drivers and loading dock folks and stock keepers that make all those supplies flow. It's contractors who are always around maintaining the facilities, it's tens of thousands of police officers who maintain security (hospitals generally have special law enforcement officers on staff).
That's a lot of people who will suddenly be on the dole or seeking unemployment benefits. You might, ultimately, be looking at a crash or a serious depression in civilisation.
As for #3, I can't imagine anyone would want to see a regular doctor when all they need to do is drink a purple potion and all their problems disappear!
All this, of course, assumes that the potions just kind of appear (as if by magic!) the way they do in games, ready to use and everyone knows what they're for.
If it's raw ingredients, then at the least you'd still need physicians to diagnose illness and determine which potion is best. You'ld still need someone to grow and process the ingredients. You'ld probably still need some nurses to administer and watch over patients while they're recovering.
And of course, you know darn well Uncle Sam will want to tax and regulate the hell out of this new industry!