Please never hide your emotions as it can cause a lot of psychological and emotional damage. I know this is true from both school and my personal experience
I decided since i was being bullied for years and everyone told me to just ignore them and not get upset to just not show my emotion(this was also before realized that I was depressed so I was surpressing that too) and this started since I was like a toddler without me even realizing it and in 8th grade when I was starting to recover from everything cause i finally moved I actually had to reteach myself how to show emotion because I didn't know how to feel or show any. And I am now in 11th grade and am just now naturally always showing my emotion so I beg you pleaseeeeeeeee do not ever do that to yourself I am only able to do that now because of how much support but it also made me easy to manipulate so please always show your emotions