Bruising can be a potential side effect of BFR training, especially if the bands are wrapped too tight. Band tension should certainly be no more than a 7/10. The combo of low iron and the shot also could be playing a factor for sure. It could also be the result of a medication or supplement side effect as well. Anitplatelet meds, NSAIDS, steroids, and anticoagulants can all have side effects of bruising. If there continues to be bruising or you notice an increase in the frequency of bruising it’s worth getting checked out by an MD.
But generally BFR is a very safe intervention and the only major contraindications include:
-Circulatory issues or clot risk (DVT)
-Severe, uncontrolled hypertension
-Sick Cell Anemia
-Open wound or incision
If she isn’t likely to have any of these she should be good to go. Wait for the bruising to settle, get those iron levels up and be sure to keep the wrapping a bit less restrictive.