What should I do?
 

Here's my only naner, Dwarf Cavendish I assume, and it seems to be sick right now. It had some mites and I killed them off so I can't find any more of them(Fortunately, I found them early enough to win this one, but I think I should always prepare for another attack) but I didn't notice that leaves were rotting and I had to cut down all the leaves except 3 open leaves and 1 leaf that is yet to be open(which is not growing at all for 3 days). The growth has slowed down significantly(It used to open a leaf once a week, but now it almost stopped growing for last 3 days) and I found that the root almost filled the entire pot, so I think I would have to change the pot. Also, other leaves are also not in a good condition, I think it's because of pesticides, and I am confused if I should cut other leaves as well. Here are the photos:

Can you see the bottommost leaf yellowing? - Also, all leaves have some 'semi-transparent' parts.

Some red on the pseudostem, Is it a sign of rotting? should I cut down this leaf?

Here is where I cutted leaves, and there is some water, would it be bad for leaves?(Sorry for the bad photograph.)

Any tips should be appreciated.

Re: What should I do?
 

Red on the pseudostem is normal.

Re: What should I do?
 

it looks fine to me
red stem, petiole edges, and leaf blotches are normal

yes bigger container
try and get some soil with a high level of POOP (find a shovel, a farm, a 5 gallon bucket)

oh.... maybe no poop inside the house .........

Re: What should I do?
 

Yo SooBak: I agree with earlier posts. If you have killed the critters (mites). Replant into at least a 3 gallon pot, looking plant roots over as you do.

Water, Watch and Wait a couple weeks! :-) Methinks it will come out of shock and be OK! Best Wishes...BrotherTom, Portland, OR. USA

Re: What should I do?
 

Consider repotting into a larger pot so it can take off and continue growing larger. As far as spider mites go, they almost always come back unless the plants are outside (from my experience) so try misting the plant daily or even morning/night or rubbing a sponge/cloth on the leaves to remove any mites before they have a chance to do damage. Should be pretty easy on a plant that size.

Re: What should I do?
 

One of the four bananas I found after Isaac looks like it went through a furnace. What's wrong with this banana again?