http://My fish has an enlarged nostril right where the normal nostril should be.
Someone, please give me a diagnosis and treatment quick so I can take the disease out.
I already added T.C. Tetracycline since the fish already has an open sore (which explains the yellow water color)
It's not eating much, sits on bottom of the tank doing nothing, and has a white spot on its head (probably ich). Someone, please tell me what the disease is ASAP.

please post the water test results.
you need to test for
ammonia
nitrites
nitrates
PH
these tests are very important so you need to take care with the test and post the actual result.

in the mean time can you do a 50% water change asap. the small white spot may not be white spot so please don't treat for that. the fish skin looks very lumpy, I suspect ammonia/nitrite/chlorine poisoning but need tests results.

Normally the guys on the site will ask you basic questions.
Have you done a water test?
What are ur Ammonia, nitrite, and Nitrate levels?
How big is ur Oscar and what size of tank is he housed in?
What other fish are in there too?

When u have done the test post the results.

And what is your waterchange schedule?

seeing unusual nostril pit and spot on the head... fish staying low,
i am suspecting bad water condition with early sign of HITH. yes, water
parameters is needed...but while not yet available, i agree that a large
water change is a must. you need to comfort your fish.

is it breathing heavily or gasping?

I forgot to tell that I change the water last night

Its like its breathing normally, but when tap on the tank the fish gives a few seconds delay to the reaction of the tapping.

You need a Liquid water test kit for Ammonia, Nitrite, Nitrate, and PH...

Test your water.... We NEED these readings to help you!

I also forgot to say that the infected nostril has white stuff lining it.

in pic he looks like yoda

without a full test you are giving us very little to go on. I would surggest you get a test kit asap before you loose your fish. until then keep changing 50% water every day and use a good water conditioner like prime.

x2