Can I repair my fridge freezer myself? (Fridgidair FR4893A)?

I have accidentally punctured my freezer whilst defrosting it.

I've tried to seal the puncture by covering it with wax but the temperature doesn't seem to be coming back down.

Is this something that I can repair by myself?

Also, having read info on a couple of other sites, I believe the appliance will need to be regased. Is this something that I can do or will I need to contact a qualified repairman?

Many thanks in advance