Why have I developed a gummy smile? I have never had a gummy smile before.

Hello doctors, I have a strange question. I have never had a gummy smile before, my teeth may not have been perfectly straight, but never have my gums shown up until the last year or so. Is there anything that could be causing me to now develop a gummy smile at twenty years old? It also seems as if my cheekbones have gotten lower as well. And possibilities as to why is causing these issues? Feedback would be much appreciated. Thank you.