External hemorrhoids form from veins that surround the anus. These veins, for reasons not fully understood, weaken in some people, causing a bulge to form. The bulge then pushes out and appears as a lump, either just outside or just inside the anal verge.
Once formed, external hemorrhoids, are sensitive to pressures, either externally applied (such as excessive sitting), or internally applied, such as straining during defecation, lifting heavy objects etc... Since the bulging portion of the vein is already weak, any such pressure tends to magnify its size and cause further tissue damage.
So, the health of these veins, at the cellular level is a critical aspect to their recovery and repair. The first thing you need to do is to provide the best environment for them to recover. This means, stopping any activity that causes undue pressure, including any issues of constipation or diarrhea.
You can provide therapeutic benefits such as the administration of sitz baths (designed to provide heat and cold therapy) as well as the indirect application of ice packs. Heat and cold both, force the body to restrict blood flow to the affected region causing a decrease in blood volume and thus inflammation.
There are also food choices that impact hemorrhoids. Caffeine, for example, is a diuretic, resulting in harder stools and increased constipation, a prime irritant for hemorrhoids. Coffee and alcohol are prime examples. Foods high in fiber are important in establishing regularity and softened stools.
Your bathroom habits, including how you clean yourself are also factors in how you can find relief from the symptoms. Over the counter products will help for symptom relief since they contain both vasoconstrictors designed to reduce inflammation and local anesthetics for pain relief.
The best thing you can do long term is to learn as much as you can about what hemorrhoids are, how and why they form, and what treatment options there are available to you.