Abscesses and cysts are painful, fluid- or pus-filled, tender masses that can occur on the skin or within bodily organs. While abscesses are infected masses and cysts are not, a cyst can become an abscess when it is infected. A skin abscess may also be called a boil, and it’s not uncommon for these to occur in places like the inner thigh and groin. Anal abscesses, dental abscesses and breast cysts are also common reasons to see a doctor. Most cutaneous (skin) abscesses cannot be resolved with antibiotic medications alone, but must be surgically opened and emptied in a procedure called incision and drainage.