This is a photo of a sebaceous cyst that has semi-evacuated itself from under the skin. The released sebum has dried up but has not fallen off. If this dried sebum piece is removed there will probably be more sebum that can be squeezed out, and should be. I do not apply anything to the area and just let it heal on its own, once the area is completely rid of the sebum deposit it heals very quickly. Like us your dog releases oil through microscopic oil glands in the skin. This oil is called sebum and helps to moisturize the skin and fur. Occasionally the sebum forms a deposit under the skin and a round cyst develops. Most of these you will probably never notice and will go away on their own.
Here is a video I found on youtube of someone squeezing a cyst. The sebum can be thick like it is in the video and it can also be more liquid or both. Color varies from white to yellow to grey. My apologizes if I grossed you out, but this is something simple you can take care of on your own. The cysts are round and located right under the skin, but are not attached to muscle nor are they irregularly shaped. I will work on getting a picture of one that not erupted or been lanced like in the video. I think you see more of them when the dogs are getting more fat in their diet, but I may be incorrect on this point. My observation has also been that they are irritating to the dog and they tend to scratch in that area. the dogs seem relieved to have the cysts evacuated.