Ding Repair - How much fibreglass to remove

Hello all,
Got a ding in my board. I'm keen to repair myself and have a decent kit with everything I believe I need to mend it properly.
My question is how much of the fibreglass do I need to remove? I'm loath to dig away more than necessary.
It's a 2-3cm dia dent where something has knocked it and it's certainly cracked through the glass. I have removed any loose glass flakes but am concerned if I just repair over what is left the crack could spread or there could be some delamination under the dent.
Are my fears unfounded or do I need to cut away the lot?
Thanks for any advice in advance
Got a ding in my board. I'm keen to repair myself and have a decent kit with everything I believe I need to mend it properly.
My question is how much of the fibreglass do I need to remove? I'm loath to dig away more than necessary.
It's a 2-3cm dia dent where something has knocked it and it's certainly cracked through the glass. I have removed any loose glass flakes but am concerned if I just repair over what is left the crack could spread or there could be some delamination under the dent.
Are my fears unfounded or do I need to cut away the lot?
Thanks for any advice in advance