First don't worry, it can be undone. Something similar happened to me and I did the following - I don't know what did the trick
1. I used my combination of oils - olive, JBCO, Sunflower, etc to soak the hair. Really saturate it.
2. without washing out the oils I saturated the hair with conditioner with slip - silicon mix and Tresseme. I put so much in there that my whole head was white. If it started disappearing I put more.
3. After letting it sit for a little while I started using my fingers ONLY to gently detangle from the ends. NO COMB or BRUSH. I started with a little section and worked my way from the ends to the roots of each section.
4. After each section was detangled I lightly twisted it - making sure it was still saturated with the conditioner.
5. After detangling my whole head I rinsed out the entire mixture because I could not find my comb BUT I recommend using a wide teeth comb and gently combing from ends to roots to remove the shed hair.
You can do it. Just don't let frustration build.