Is washing the lower part of the proximal nail fold obligatory in ghusl?

The proximal nail fold is the term for the fleshy part directly above the nail matrix or nail root. The lower part of the fold which is directly in contact with the matrix or root is supposed to be sealed but in my case it is not and water can seep in. Is washing this part during ghusl obligatory? Click [here](https://d2jx2rerrg6sh3.cloudfront.net/image-handler/ts/20170110083447/ri/590/picture/nail%20and%20finger%20tip%20anatomy%20-%20gritsalak%20karalak%20_thumb_1.jpg) to look for the part in question