I normally use just plain old coconut oil with some essential oils added as my lotion, but during P2 I can’t do that.
Since no fats are allowed, you also have to be careful which lotions and beauty products to use. Avoid ones with food oils in them. i.e. – almond oil, avocado oil, palm kernel oil, macadamia nut oil, olive oil, coconut oil, sunflower seed oil, sesame oil, borage oil, cocoa butter, shea butter, and neem oil.
Castor oil, mineral oil, and petroleum jelly all seem to be okay. And any silicone based ingredient is fine. I seem to do fine with Bath and Body Works products during P2, but again, everyone is different. As long as your lotion doesn’t have one of the above listed oils in it, you should be fine.
If you use the lotion and have a gain though, I’d stop using it and see what happens. Maybe try again in a week and see what happens. That way you can be sure that the gain was related to the lotion.