Hey there, and welcome to the forum!

I don't really have any traumas or stuff I'd like to forget (well, except for the bipolar part, I'd gladly forget about that!). I just wanted to reply to your particular problem here.
It seems you really love the surgery part of your training. Have you ever considered seeing a therapist for these issues you have with the self harm? From what you're saying (and please correct me if I'm wrong), seeing and working with the surgery triggers memories of self-harm, and maybe even intention of self-harm. It's probably the association your mind instantly makes between the two things. Behavioural psychology is very useful for stuff like this. I'd say the same principles that work for phobias could work here - it's all about breaking the link between the stimulus and the negative outcome.
I hope you don't take this the wrong way, I'm not trying to tell you what to do or anything. Just thought you'd like to know. It has very high success rates, although it needs some time to work. It won't make you forget, but it'll probably help you deal with it.
In any case, I hope you can overcome that and be happy and successful as a vet!