Yes, it matters a lot. I use Forge WebUI (also via Stability Matrix), I know inpainting is more tricky in ComfyUI. I use options similar to the ones oin the screenshot below. Important things to note:
1) Masked content - what should be used under the mask, I always leave it at "original" to use the original image
2) Inpaint area - "Whole picture" for major elements dependent on other things around it (limbs, patterns, etc.), "Only masked" for small, detailed, independent elements like eyes, cutie marks, jewelry, etc.
3) Denoising strength - how much do you want to change the original masked content, I usually set it to values in range of 0.2 - 0.4, depending on the situation
4) Sampling method, resolution, CFG Scale - leave them the same as in the original image
[Inpainting options screenshot](https://pomf2.lain.la/f/v0o6uojw.png)