My question is: What is the ruling on using a "pouffe" comb for hair?

If the comb mentioned is merely a tool used for combing, then there is no harm in using it, as long as it does not cause harm or involve imitation of disbelievers and transgressors. The basic principle regarding things is permissibility, and harm is to be removed. It is forbidden to imitate harlots and immoral women in their manner of combing, as mentioned in the interpretation of the Hadith "Two types of people from the inhabitants of Hell," concerning women who are "clothed yet naked, inclining and causing to incline."