Pcr blood test for hsv1 & hsv2 both negative 7 weeks post exposure. Is this a reliable test vs igg antibody testing?

HSV testing. Both are good. A PCR blood test looks for circulating viral DNA. The IgG look for the development of an antibody against the virus. If these are not present 7 weeks after exposure then the most likely conclusion is that you did not acquire it.
Definitely. PCR over blood testing any day. Blood testing is limited in telling you what's really going on.