It's not hard to google some statistics on prevalence and transmission rate of different types of STDs. In general the risks of BBBJ are quite low, pharnygeal gonorrhea is amongst heterosexual interactions are quite low, and the transmission rate is not great. Other rates of STDs like herpes and HIV are even lower. However that doesn't mean there is no risk, with each exposure your risk obviously increases. It's just a probability game, eventually you're gonna roll the dice and hit snake eyes. So the most important thing if you are not protecting yourself at all times, and enjoying a bit more risky behavior like BBBJs is to get tested periodically, whether you have symptoms or not. I suggest testing every 3 months at your local GP or sexual health clinic.
Alot of symptoms with the common STDs (ie. gonorrhea, chlamydia, although trichomonas is creeping up) is very vague, even more so for women. So you can be contracting it from your favorite WL and they don't even know they got it. For men, it's still over about 60% of people not having any symptoms for up to 3-6 months with gonorrhea and chlamydia, the most common symptoms being some abnormal discharge and painful urination. The problem with not having symptoms is it can cause some serious long-term health effects. Unlike herpes that the OP is worried about (which mostly only causes symptomatic painful outbreaks and embarassment), gonorrhea and chlamydia can cause permanent infertility, pelvic inflammatory diseases and epididymitis (your balls become super swollen) requiring surgical intervention.
So TL;DR, BBBJ is "relatively" safe especially compared to BBFS but you should be getting tested every 3 months to make sure you are covered and not spreading diseases.