Hello, Jini!~ 

I commend your effort in making sentences. Keep it up!~ Great job!~ ^^

Kindly check the corrections. Hope you find these helpful.~ ^^ 

--Lynda^^ 

CORRECTIONS:

The weather was getting chilly, the patient increased.

--> The weather is getting chilly so the number of patients have increased. 

My throat is getting hotter.

--> My throat is getting ill. 

I have a fever but I don't know reason.

--> I have a fever but, I don't know why. 

My sore throat is not getthing better until last week.

--> My sore throat is not getting better since last week. 

A cold usually accompany sore throat and cough.

-> A bad cold usually accompanies with sore throat and cough. 

You have to take pills to symptoms.

--> You have to take pills if you feel any symptoms. 

If you feel suffy that you have a pill.

--> If your nose feels stuffy, you have to take a pill. 

This illness don't have medicine.

--> This illness cannot be treated with any medicines. 

You have to wear layers because ouside is freezing.

--> You have to wear layers because it's freezing outside. 

Keeping warm body is good at protecting illness.

--> Keeping your body warm can help you avoid disease.

Symptom was getting bad, and the doctor uses more strong pills.

--> The doctor prescribed stronger tablets as the symptoms worsened.