Another option is using heat and aloe vera. You will need a heating pad or a few clean towels and a large mature medicinal aloe vera plant.
Apply heat using a heating pad if you have one handy over the cyst or use several clean warm towels one at a time to keep the cyst warm for about 15 minutes 2 times a day. Be careful to use a clean cloth between the heating pad and cyst if you use a pad. DO NOT use a high heat but a nice warm heat. This will encourage the hardened sebum deposit to melt and hopefully be reabsorbed by your body.
Cut off a piece of a leaf from the aloe vera plant in a size that will cover the cyst. Slice the leaf open in such a way that one side is very thin and most of the other side has lots of the aloe vera gel then place it over the cyst with the gel side touching the cyst. Lastly, place a clean bandage over the aloe vera leaf it to keep it in place . Do this after each heat treatment. You may have to do this for several days or even up to 10 days. Do not scratch, pick or squeeze the cyst.
Aloe vera not only heals but it has an antibiotic action. If this does not work for you, your only option may be surgical removal and antibiotics.
I would see a dermatolgist and have him/her take care of it.
The liklihood is you will require the assistance of a physician to surgically excise the infected area, suture the skin and then provide you with follow-up antibiotics. Once these infections become established and encapsulated, surgical excision and draining is often the only option.