My creatinine reading was 138, can it be 100% treatable ? or reduced ?

Depends: Depends on the cause. It is slightly high- if it is acute or because of some medications it may come down on stopping them. If it is chronic it will not. Your doctor will be able to figure out the cause and help slow down the progression. You should have it evaluated- you are young.

Depends: Serum creatinine of 138 mol/L is equivalent to 1.56 mg/dl. I agree that your renal function is abnormal. However, whether it is treatable depends on the etiology of renal dysfunction.