I would suggest going to the doctor for an injection, this will assure you of no scarring.
You can also buy some BP in the pharmacy or sulphur.
Or you can buy tea tree oil for spot treatment.

2 hours ago, Yasminexra said:

Hi so I really need advice !!

I've always had acne but never really a cyst. For this long underneath my skin.

It started with an inflamed huge pimple on my chin but now after a week there's still a huge bump underneath my skin and there is no white opening.

What should I do?
Wait ? Make an appointment? Needle it myself? Help

First, try to bring down any inflammation, which is the main culprit behind scarring. Apply ice and take 2 aspirins for the next 3 days. Rubbing tea tree oil can also help. If inflammation persists after 3 days, then you might consider getting steroid injection like kenalog.