There are two kinds of hemorrhoids: internal, which occur in the lower rectum, and external, which develop under the skin around the anus. External hemorrhoids are the most uncomfortable, because the overlying skin becomes irritated and erodes. If a blood clot forms inside an external hemorrhoid, the pain can be sudden and severe. You might feel or see a lump around the anus. The clot usually dissolves, leaving excess skin (a skin tag), which may itch or become irritated.
Internal hemorrhoids are typically painless, even when they bleed. You might experience painless bleeding with blood bright red blood (on the toilet paper or dripping into the toilet bowl). Internal hemorrhoids are prone to prolapse, or extend beyond the anus, causing several potential problems.
Besides adequate hydration and a high-fiber diet to AVOID CONSTIPATION (you may even require laxatives), Sitz baths (warm water with iodine-based solution to relief itching and disinfect the area), local (non-invasive) treatment consists of over-the-counter creams that are based on local anesthetics (for temporary pain relief) +/- cortisone (reduces the inflammation and swelling). Since these creams contain cortisone, it is not advisable to use them for more than 7 days and without a physician's supervision.
Note that some hemorrhoids do not respond to conservative treatment in which case you will need to consult a surgeon for surgical treatment.