My fragmin/dalterparin daily injections are leaving hard lumps up to 2 inches at injection sight they don't seem to be going for weeks. causes?

Bruise: Seem bigger than expected check needle size, volume injected and talk with doc about possible overdosing. While a goal of anti coagulation is important, local bleeding is uncomfortable and a possible sign of need for adjustment. Ice may help earl, and heat later to limit bruise and resorb hematoma.

Numerous reasons: One in particular is the "rotation" are you rotating the injection site? If not talk to your physican on how this is done.