Mast cell removal, only able to get small margins

Hi all. My dog has MCT removal on hip/thigh area today. First timer. Due to there not being much loose skin there, vet called prior to surgery and said the margins would be small. “Surgical excision of the mass on the left lateral thigh was performed.

pre-operatively that due to limited skin laxity, margins would be narrow approximately 0.5-1 cm”. We were told biopsy results could take a week or so to come in, and I’ve been anxious ever since as when I’ve searched subreddits about this, I see a lot of people comment that large margins are taken to try and ensure clean margins? For an area where this can’t be done due to thin skin, I want to know what next steps will be if they come back not clear. Does it depend on the tumor/mass grade?