I had red pixels in black spaces on the screen. I opened my macbook 13 and just blew some air at the sockets of inverter cable and display cables. The red pixels vaninshed for a month or so. now I have the same problem but it goes away if I press somewhere at the bottom of the screen at the hinge connector. So I suppose it must a connection problem. I will order a new inverter and display connector and replace them. I will keep you posted.