The ankle thing is probably a bug bite that you can't even see - think its one of those random non-cancer things but you may have to look into it at some point if it doesn't get better.
The lump thing is probably nothing too but does need to get looked at right now so it is good you are getting an ultrasound. My recommendation is DON'T touch it at all anymore. When we get a lumpy/bumpy, all you want to do is touch it and that just irritates it more so it can't heal/drain whatever. You know how big it was so don't touch. Not at all. NADA. The day you go for the test, when you are showering - give a feel. Your fingers will remember and you will be able to tell if it has changed. It will probably be smaller. No rubbing and touching. No, no, no
I agree with you that you are right about not changing doctors this moment but you just might need to because he uses this nasty nurse as his defensive end. I have a doctor who will call me directly and has when I was in treatment and the first year out when you think about everything. Remember, these people are folks you hired to make you well and save your life. They are your life saving employees and you can certainly fire them and hire another at any point. But get through this ultrasound (and get a copy of it) and see what's up. Certainly if you don't like what they say, a second opinion is in order.
Get that hand away from that lump girl!