Hello, I can help you with this. How big is the section of frost?
If the frost goes all the way across the machine and is more than 6" tall you have either a stuck thermostat or weak compressor. If you have only a 6" circle patch more on the left hand side then you have a leak of the refrigerant called an evap leak. Let me know what you find and i can help you with the next step.
I see we may be having issues with chat, I'll switch to Q&A.