Sebaceous cyst on scalp

I've had a sebaceous cyst on my scalp for around forty years. Just a small hard lump, slightly rough to touch. Earlier this year it began swelling and felt softer, smoother. It itched and was tender to touch. I saw my GP who said it had become infected and prescribed Fusidic Acid cream three times a day. This appeared to work, the discomfort/itching gradually went away but the cyst did not shrink. It did, however, become hard again and then last night it fell off. Just a pea sized lump that hit the floor like a pebble and looks like a bit of melted plastic. It has left a hole that is sore and moist and in seventeen hours as not scabbed over.

Should I put anything on the wound? Will the cyst return?

I am seeing my GP on another matter on the 31st, is it okay to leave this until then?