Swollen and throbbing inguinal lymph nodes (rock hard) size of a large olive? No fever.

Need to see Dr. These nodes need to be seen by a dr for diagnosis, as you could have a serious problem.
See your doctor. Lymph nodes enlarge for two main reasons. An inflammatory (ei: infection) or infiltrating process (ei: cancer like lymphoma). See your doctor, a course of antibiotic is appropriate and if it persist then an excisional biopsy should be done.