I wouldn't try to solder to R78, you will likely lift the resistor. Yes, try chopstick/nail method by touching side of R78.
My only concern is when you lifted the solder pad linked to R78, whether or not it may be through hole plated to something on other side of the PCB, and the link is now broken.
imho, I think you'd be better off starting over with another undamaged HH5a and get a PL2303TA or similar serial-TTL to USB adapter.