i have had sebacious cysts on a few of my girls, Ellies was on her rump (1cm diameter), the vet tried to establish if it was an abscess or cyst by drawing out some of the contents with a needle. It was thick & non odorous, so decided it was a cyst. the vet cleaned it out by squeezing it through the puncture hole, it would keep refilling every few months, but the vet said to clean it gently when it was full - it was actually easy as the puncture hole never healed properly so i could just gently pick the scab off & the contents (cottage cheese consistency) would come out with gentle pressure (no hard squeezing anyway as it could cause infection). She had it when aged 5yrs for about 3yrs with no real issues - i would discuss with the vet about monitoring it for size & shape changes, mobility issues, etc.
My Orca has a lump above her eye/on forehead looked like a pimple for years, but now it's grown to a pea size, the vet has measured it & want me to monitor it for changes, taking her back if any issues.
if Lottie hasn't enjoyed good health i'd probably be inclined to leave surgery as a last resort too.
@Merab's Slave my Rainbow bridge Ellie had the HCG hormone injections twice (once aged 6 & second batch aged 7), they worked brilliantly for her

try looking through this old thread
Ellie- Ovarian Cyst,maybe Stones, Suggestions Please.