I too am suffering from Serious cavity filariasis. I think its Mansonella Ozzardi (one of the three types). Ivermectin gives me some relief but only when I take it every day at 24 mg or more. I have the cysts under my skin that I thought were colesterol until you mentioned it. No parasite test has ever come back positive as this parasite is a cavity dreweler more than an intestinal one. I have a nearly constant presence on my skin. The only test that can accurately detect them is a PCR test that appears to only be available in Brasil
My experience is that they will leave your body and take refuge in suitable places. They will reinfect you from there without completely abandoning the refuge. You have to spray pesticide to get rid of them. It is also my experience that they can travel through the air by springing their bodies. In this way they are highly contagious. However not everyone is susceptible. In particular women are not a preferred host. Mostly its middle aged men. This is case in Latin america were they are endemic, according to literature.
The adults can live 15-20 years deep in your tissues. There is no pharmaceutical way to kill these. Surgery is the quick option. I was hopping that the ivermectin would allow me to wait them out. I keep getting reinfected from those living in my house etc. It has been my experience that once separated from you they become quite aggressive. If they get in to a winter coat i have to throw it away.
All but a very rare few doctors will tell you that you are crazy ("something wrong with you"). the only advice I have is to keep dropping them until you find one that will help you and believes you. I went through more than a dozen.
I hope this helps. Currently I have no hope of ever being free of them. Salt ( Epsom Salt baths and table salt comsumpsion) and sometimes ginger. Perhaps if I moved to the beach and burnt all my belonging everyday and someone gave me new stuff I could get rid of them. Otherwise they always find a way to hang on.