What would be the most effective remedy for cure an "open" infected sebaceous cyst?

Let it drain. See a surgeon and possibly get it packed. May need antibiotics.
See Surgeon. Sometimes antibiotics can cure an infected cyst. If this fails, it is possible that you might need surgery to drain infected material. If this problem recurs, you might need to have the cyst surgically removed.

Related Questions

If I have an infected sebaceous cyst do I have to get it treated or will it go away with time? I don't think I can get it treated for a while.

Will need treatment. The cyst will not go away on its own and will occasionally flare up and cause you pain and discomfort, even if you are able to treat it successfully for the time being with antibiotics. It will be much better to cool it off with antibiotics and then have your plastic surgeon remove it entirely. The surgeon must remove the entire capsule with it to avoid a recurrence. Be well, dr. Fred. Read more...
Yes. Infected sebaceous cysts may drain spontaneously, but can also evolve into subcutaneous abcesses. Don't risk flesh eating disaster by delaying treatment. You may try warm compresses to encourage it to drain. Read more...

Had an infected sebaceous cyst removed 2 wks ago. No stitches; daily dressings. Has been healing well. Suddenly, I notice redness around the wound.?

See the doc . That removed the cyst as it sounds like it is becoming infected. Read more...
Sebaceous cyst. Any change in the skin area suddenly could mean that infection is starting. Because the cyst was infected, that infection could still be there or perhaps additional bacteria from the skin has gotten into the healing area. An increase in redness in the area should mean a follow up visit to the physician who removed the cyst. . Read more...