Can really bad bruises on your arm from being grabbed really hard cause blood clots?

No: Blood clots rarely, if ever, form in the arms. If the injury is due to domestic abuse, you should contact the police. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex. Get HPV vaccine.