Live and learn! Unfortunately, this accident will be the first of many, hopefully the rest will be less severe.
Hopefully, if your husband does have an angry reaction, it is just due to his own frustration/guilt of not being able to be there to prevent it. A quick snap reaction because of the shock of seeing your baby injured. Hopefully, he'll bounce back quickly and be supportive of you and nurturing toward your son.
My daughter is almost 5, and both I and my husband have been on "single parent" duty for lengthy periods of time due to the responsibilities of our jobs, so I understand how hard it is to get the simple day to day necessities done, like cooking, forget about the luxuries of really cleaning your house. I hope you have relatives or friends nearby that you can lean on for support!
I would just try to have several options available when cooking, bouncy seat, doorway jumper, pack and play, highchair, so you can move him from place to place if he's bored. Also, maybe he can bang on a pot with a wooden spoon - if you can stand the noise.
Stop beating yourself up (but do make sure it doesn't happen again). We're human, your son will heal, and you need to be ready to handle the next injury, which hopefully comes later not sooner.