Just my opinion, but I think there is little or no relation between AN treatment and temper or mood. What is the etiology (causation)? Sure, it can be stressful to receive an acoustic neuroma diagnosis, decide on treatment, and undergo surgery or GK. But, can having a benign tumor in your head directly cause a bad temper or bad mood? Doubtful.
What else might be the cause of a bad temper or bad mood? Poor diet, lack of exercise, smoking, alcohol or substance abuse, depression, social anxiety, bad job/career, unfulfilled dreams/aspirations, bad marriage/relationship, angst about wars, poverty, elections, etc.
Personally, I consider my AN as something of a blessing - in the sense that my worst health challenge (so far) has been to have an acoustic neuroma. It could be much, much worse. I have two close family members who are dying of cancer. Several close friends of mine have autistic children. My brother-in-law drove himself to a hospital several years ago with flu symptoms and died 6 hours later of bacterial meningitis (he was 33). I've known other family or friends who've had epilepsy, heart disease, Alzheimer's disease, etc.
Life can be hard. It can also be glorious. Sometimes it depends on the lens you're looking through.