Sebaceous cyst inflamed dangerous?

Not really but.. Abx will NOT cure a sebaceous cyst. They can help clear the infection and surrounding cellulitis that can occur when the cyst becomes infected. .... but not the cyst itself. The cyst needs to be removed if bothering you. If not bothering you can be safely watched. .
No. If it does not drain by itself you may be able to squeeze it out. Your dr can open ; drain it if needed. An antibiotic is of no value unless there is spreading infection. It does not matter what you put on it.
Not if it is treated. Properly using apropriate antibiotics and surgical drainage when necessary, assuming normal immune function. Show it to a doctor for specific advice.

Related Questions

I have 1cm-lumb on my nape. It is hard, does not hurt and it is skin colour. Can it be sebaceous cyst, lipoma or more dangerous?

Likely no need to worry. at 1cm, your lump is not too worrisome. If it grows or changes in any way, I would have a biopsy or excision. This is likely to be able to be done in the office. If it is a sebaceous cyst, it will be attached to the deep layer of the skin. It is important that the entire thing is removed and not just lanced open. O/w it can return. Read more...