I had my lips lines filled 4 months ago. Will they still swell when I have oral sex?

Thank you for your question. It is unlikely oral sex has caused displacement of your filler. I recommend avoiding this for 1-2 days after your treatment or until all swelling has resolved which can take up to 2 weeks. I recommend addressing your concerns with your injector. Best of Luck!

Fillers injected into the lips will cause swelling and will take about a week or so to settle down. Best of luck with your results.

Both around the eye and the lips are areas that take very little to swell.  I don't think that this is directly related to the filler you had in your lips, although if it was a hyaluronic acid product that holds water, any constant and continual use of your lips as with oral sex, can cause swelling.  As long as it goes away in a couple days I wouldn't worry - and sleeping with your heal elevated and applying ice after this activity may reduce the swelling.  OR ELSE, if you were performing oral on a condom, you may be allergic to something in the condom...or to a lubricant perhaps?