3 yo has bruises on her knees and shins. one bruise has a white spot in the middle that is a hard lump size of a pea. is this normal for a bruise?

Bruising: Toddlers get lot of bruises due to frequent falls. Common sites as you mentioned, knees, shins. Bruises at different ages of healing are seen in this age group. The harder pea size lump may be a lymph node swelling within the bruised area. Lymph nodes catch bacteria, gets bigger, kill them, then slowly gets smaller, come back to its smallest size over 2-6 wk time. If still worried, talk to her doc.