Hi everyone, thxs for the comments! I took them all into consideration

So this is my final day scene image! Yay! I changed up the lighting quite a bit and added some sun rays to help with the light on that side of the room. I changed up the celing to be mossy and to make it like water had possibly leaked in and gave it some damage.
The only thing I dont like and would probably change is the celing, because it looks like its really specular at the moment.
Oh and to answer the question- The white stuff on the walls are the paint. I tried ot make it look like the wall was not painted evenly.
Hope it looks alright to ya'll , Ill be posting the night scene soon.
thx again!