The background of the cosmetics taken in the studio is very dark. What should I do?

Brighten the background with single light (double light or single light is ok). Then use single lamp or double lamp cloth to polish the product theme. The power of backlight is higher than that of headlight. If the backlight power is 300W, 100-200W turn on the headlights, 1/200 try exposure, and the aperture is f/ 16. Try it, maybe the effect you want will come out. Wish you success!