It wasn’t in her arm but my mum had multiple clots in her lungs from suspected DVT, and had to go on blood thinners for months (in her case it was the injections but this was before the BC), but they have all cleared up and she’s off blood thinners unless she flies then only for a couple of days per flight. Depending on the circumstances, it can take months or medication adjustment, but yes typically with treatment the clots go away. I’m not a doctor, just lived experience with my circle 🌺