After explant, what happens to the "pocket?"

Thank you for your question.  The body begins to close up the space that once had the implants.  There is shrinking of the tissues to a degree and contraction of the muscle as well.  The quality of one's tissues, size of implants removed, age, and duration of implants all affect the degree that the tissues will collapse.  An older patient with larger implants for a longer time is less likely to go back to a preaugmented size than a younger patient with smaller implants for a shorter duration.  

After explantation, which is the surgical removal of a breast implant, the body typically starts a process called capsular contracture. This occurs as the body's natural response to the presence of a foreign object, such as a breast implant. The tissue surrounding the implant, known as the capsule, may gradually shrink and tighten.
In some cases, the capsule may partially or completely dissolve over time. However, in other instances, especially if the implants were in place for a long time or if there were complications such as infection, the capsule may persist. If the capsule remains and causes discomfort or distortion of the breast shape, additional surgical intervention may be necessary to remove it.
In cases where the capsule remains intact and does not cause any issues, it may just become a part of the body's natural tissue and remain in place without causing any further problems. However, it's essential for individuals who have undergone explantation to follow up with their healthcare provider regularly to monitor their breast health and address any concerns that may arise.