iPhone 5 screen is acting weird

My iphone screen suddenly acts weird last 4 days, for example i'm browsing facebook when suddenly the screen freeze or so i thought because i can't scroll down and touch the assistive but when i push the home button it directed me to the home display so it means that the screen didn't freeze it only happened for about 5 seconds, and sometimes when i zoom in i can't zoom out again the picture is either going up or down and then when i tried to compose new message the screen didn't respond and sometimes when i'm trying to swipe the home screen it is swiping but slowly all this is happening for about just 5 or 10 seconds, then it is clicking by itself and just last night i'm scrolling it, it is scrolling but when i touch the words it is not responding, sometimes i can type but when i'm clicking send it doesn't respond but i can still type and it is normal for the top right part of the screen to be warm? All this happened when i upgrade to ios 10.1.1 5 days ago i don't know if that is the problem and i also have a little bit sweaty fingers and i dropped my phone for maybe 6 weeks ago i don't know what's the problem and i smelled the charger and heaphones port, sim card slot, the speaker, handset and the side of the screens it smells like mold or something is it bad?