Sundae has quite an active grease gland, and lately it has been acting up a lot and she has a permanently greasy spot just at the end of her back. The fur gets very clumped together. I've been cleaning the area as best I can, but it seems to hurt her (she spends the whole time biting the blanket she's on in a panic) and today I noticed an area where the skin itself looks normal but there seems to be some fur loss. Does anyone have some recommendations? Products that are specific to guinea pigs are hard to come by here, but is there something generic to help clean the area and soothe any skin irritation?