Eh, I just looked through official church records over the last 3 years of all missionaries that died and this case does not exist. A lot of people are trying to say "Oh, well they are sweeping it under the rug" which is an unlikely scenario one, considering the friends and family this girl would have had that would make this more known. So, I looked up death records in Oregon for anything relating to this girl and they are non-existent.
If I knew better, I'd say that this is maybe an emotional fluff piece to draw out reactions from people, as it really would be an atrocity. But, as a former missionary myself, there are some holes and flaws with the story. For example, unless she was involved in some kind of accident that caused serious dental damage to herself needing surgery, no missionaries are approved for service unless they have been given a clean bill of health from their Dentist as saying they will need no dental work over the next couple of years. For most people this means that most missionaries get their wisdom teeth pulled before they leave on their missions, to avoid the potential complications there. However, she went under serious dental surgery, implying more serious issues that wisdom teeth extraction. If she really needed this work, this would have been quite easily seen by a dentist before she left and she would not have been approved to leave.
Furthermore, the explanation of her leaving the hospital early because she seemed to be doing better? Then she died the next day? Really!? This is such BS. What hospital ever released someone that went "septic," as in had a serious bacterial infection, which means their white blood cell count would've been through the roof. Yet the hospital released them? No one gets released from a hospital with a high white blood cell count after going septic. If the situation is true like the OP has stated, that hospital would also be in some serious trouble in risk of a major lawsuit right now. Release someone from the hospital who then died of septic shock? Really? Ya...
Plus all this talk of having to get permission from the mission president's wife to go to the doctor... what!? This thread is filled with lots of weird posts about how the church makes people cancel their health insurance to only use theirs and so on. Again, another made up thing. Why? Because I had double insurance on my mission, and the church was all the more happy because of it, even encouraged it. I had the insurance from my parent's work, and I had the church's own insurance. No one actively encouraged me to cancel mine. Again, the logic behind that makes zero sense. I knew plenty of missionaries that got sick and ended up in the hospital, I was in Africa after all as a missionary. Do you inform the mission president? yes! But, it's usually as you are driving there or after the fact... We never had any rules anywhere that stated you couldn't go to doctor's without permission.
Again, if this whole thing is true fine, I agree, there absolutely should be legal action taken. But, it really seems made up.