If you bought it Retail, brand new I would return it for replacement. If you bought it 2nd hand and the phone works OK and the Touch screen works fine-live with it. The Touch screen glass you bought/buying requires a heap of skill and special care and tools to replace. If you have no experience in this field, I would advise getting specialist service agent to do the job. This could cost $80-100.00 to get done. I have preferred to replace the complete assembly (LCD screen and Digitizer) as these are available for $140.00 upwards. I've done this on 4 S4's but they were major glass breakages and were not showing anything on the screen when switched on. The phones were i9500, i9505 models. Neil.

 

Totally agree with nu2andy. Replacing is not an easy job. Search for some youtube videos and watch a few before making up your mind...