Loud, long beep from my Oculus Quest

Hello. I couldn't seem to find much content on this issue online, so I'm looking to discuss it here. I bought this second-hand Oculus Quest from someone that has been using it until recently around mid August, and have been using it for development in my research. I would spend around 8 hours developing per day, and I did notice that the headset would get hot sometimes. A few days ago, a system alert notifying that the device's fan wasn't working properly. I was worried about it so I stopped using it for long hours at the time, but when I turned the headset on and tried putting on my head, it made this loud, singular beeping noise that never seemed to end. The sound stopped when I turned the headset off. After a while, I turned the headset on and it didn't make any noise, but I was too scared to put it on my head, so I just turned it off again. 

Is this headset dangerous to use? Can I still keep using it? I'm really troubled on this because my project with a deadline will really be stuck because of this problem. I would be thankful if even just one person would reply to this T-T