Explaining self harm to young children

[FaithLoveandHope]

I self harmed pretty badly last night and as a result have a bandage on my arm. How on earth do I explain this to 4 year old DSD when she gets up? She's naturally going to ask why I've got a bandage. I can say I hurt my arm but if she probes further I've no idea what to say...

Personally I wouldn't mention anything about the fact you harmed yourself intentionally.
4 is too young to be made aware of these thing in my honest opinion.
Can you just say you cut your hand while cooking or caught it on a door or gate?
I don't think it would be fair to burden a 4 year old with the truth.

Yes cooking is a good idea, thank you. I'm so bad at thinking of excuses but that would definitely work