Increase in butt size after lipo on thighs and butt?

Hi there,
Liposuction helps in removing fat cells from the target areas. There are fixed numbers of adult fat cells in the body. 
Liposuction removes the desired amounts of cells, the remaining fat cells tend to hypertrophy and enlarge in size to accommodate the excess energy. 
Hence increase in size after liposuction is not uncommon if calorie intake and weight management are not taken care of.
Liposuction can be repeated in the already operated areas 3-6 months following the previous procedure to enable proper evaluation after the tissues have gained normalcy after liposuction. It's true that not all the fat cells are removed during liposuction this is to ensure acceptable contouring of the target areas.
Hope that answers your question.

If you gained appreciable weight it is possible to gain increased size of buttocks from fat cell remaining becoming larger.   Get back to your original weight at the procedure.   Yes you can have additional liposuction.   Watch your weight.   My Best,  Dr Commons