Hiya,
3) I'm a student midwife and I have scaring (albeit not horrendous) on one of my arms, at one point they were quite red still, but now are very white. I haven't had any issues with them, I told my first few mentors because I was very anxious about them, but they were fine with them. Occ Health weren't concerned with them either, as long as they are healed.
I've never had any 'patient' or visitor mention them, including on my 3 months general nursing. At one point when I had healing wounds I wore a tubi-grip and anyone that asked I just said I had a nasty wound I needed to cover, the only person that questioned me lots and was rude was a doctor.
When they were quite red still I put foundation on, except this is pointless if you're going to be in theatre and 'scrubbing' because you have to wash up to your elbows (I did this once, wasn't a huge problem as i just put it back on when I'd finished in theatre)
Basically, chill out
people don't see what they don't want to see
for 4 & 5) I've struggled on and off on my course due to life circumstances and MH stuffs, my tutors have been very supportive, I had counselling at uni for almost a year. I had to 'step off' the course for 6 months due to MH stuffs and I repeated the 2nd semester of my 1st year. Basically, I've had lots of crap during my course and uni have been great and very supportive
You'll be fine!