could it be a bug bite or std on my boyfriends penis?

[treebetch]

Yesterday my boyfriend told me he had a mosquito bite on his penis. I looked at it and it was on the shaft and honestly the lighting wasn’t good so I couldnt tell what it looked like. it didn’t look like a bump, just a little red spot.
We’ve been having unprotected sex for like 2 1/2 years and I’ve been tested for STDs before and haven’t had one. But he’s never been tested for stds before and he’s had partners before me.
Now I’m 30 weeks pregnant and this is a concern for me because i have no idea if it was just a bug bite or something like herpes.
I got tested for STDs at like 12 weeks but they dont even test for herpes unless I ask. They only tested me for gonorrhea and chlamydia and also blood tested for hepatitis.
He has bug bites on his leg  but being pregnant I’m still very worried it could be an std because we’ve been having sex and I don’t want any chance to pass it on to my baby. He said he’s absolutely sure it’s a bug bite but I’ve heard herpes can be dormant for years. Any ideas?