What is the scariest medical symptom you ever had?

[MrsPete]

Shooting pains down my left arm. Of course I was thinking heart attack, but it turned out to be a pinched nerve. $5000 in hospital tests, and they fixed it with a single prescription.

Bell's palsy - went to Urgent Care and then to the ER where stroke protocol was initiated before I even received my hospital bracelet. It was a scary, but thankfully short, time, and I will never complain about a long wait time in the ER again.

I had Bell's Palsy recently. Once I found out what it was, I honestly wasn't that upset -- my doctor told me it has a 97% chance of resolving itself if you do nothing, and the steroid she gave me raised my chances. Sure enough, a month later I was myself again. It wasn't pleasant though.

 

[AlexLap]

Bleeding after my wisdom tooth removal.
I went to the dentist and had a tooth pulled out. It was scheduled, so I expected that I would experience pain and discomfort on that day. The procedure wasn't long, everything was fine. I came back home, took all the prescribed meds, and even double-checked the info about them on the Canadian Pharmacy site, and after several hours bleeding started. I couldn't stop it on my own, so I went to the hospital. I spent three days there until they allowed me to come home.
I have one more wisdom tooth to pull out, but I'm still mentally unprepared for that.

 

[NannyBeBe]

It's a toss-up between a lump in my breast, which resulted in a mastectomy, and my first bout with vertigo, which was very frightening.

 

[nene0182]

Either, a lump in my breast that was monitored as a cyst for over a year but ended up being triple negative breast cancer or a swollen eye while dealing with a sinus infection that wouldn’t go away. Turned into orbital cellulitis and I was hospitalized for 6 days, on two IV antibiotics then 2 courses of pill antibiotics after that and had “emergency” sinus surgery.