Cyst removal and seroma - Can incision close but the fluid remain inside?

In 9/12/2022 i made a surgery for a deep in my buttock cyst removal. Now after a seroma i recover very slow. The fluid is decreased a lot and the incision starts closed ( it opened by itself and a little from doctor). But the skin around the area from wich the fluid appeared is still very hard and i feel pain when i touch this whole spot (no redness no warm, i take also antibiotics). Is it normal; Can incision close but the fluid remain inside;