TMI question need help

I hope this is a ok group to post this in. It’s a weird question and I would ask my dr but it’s almost awkward to talk about😂 I’ve noticed for the past 3 maybe 4 months during and after oral on my boyfriend that under my tongue swells up and hurts. I know it’s the salivary glands but I’m not sure why they’re swelling and why it’s every time. Sometimes it causes under my chin to swell and get hard as well. I tried to briefly bring it up with my dr but did not mention what triggers it and she said it could just be from allergies. We don’t use lubes or anything so I know that and it’s only during and after oral and also whenever my mouth makes a “sucking” motion or whatever, it just swells up and hurts and only partially relieved when I eat sour or salty things to force my mouth to water😩