Can expressions like crying and laughing cause lip filler migration in the first few days?

I wouldn't be too concerned about minor movements like smiling and laughing. There are a handful of things that I typically advise against for a few days after lip filler, like drinking from a straw or chewing on/biting your lip. After a few days, there isn't much to worry about. Much of "migration" isn't really migration of the filler itself, but rather filler that wasn't injected in the right place to begin with, or the water attracted by certain fillers, so choose your injector wisely!

Minor movements such as smiling and laughing should not impact your filler results or cause it to migrate. I encourage you to discuss your concerns with your injector so that you are comfortable and confident in your treatment.

The filler has to be dissolved with enzyme otherwise it will remain and never resolve naturally.Once the filler is removed you should be back to normal. Recommend going for an in-person consultation.