I am not sure why you got a bumpy appearance after Bellafill, if the filler was placed under the orbicularis muscle. Before you consider fat transfer, I would get the matter of possible need for removal of Bellafill settled first. Once Bellafill is removed, I would wait at least 2 to 4 weeks before fat transfer to make sure any possible swelling from Bellafill removal has resolved.
Thank you for your question, and I'm sorry to hear you are having troubles with the filler product. No, I would not do the fat transfer to the same region at the same time as removal of the filler. It would be very hard to know how much fat to inject at that time. This could be done down the road a bit (6-12 weeks). Best wishes.