Eternoui, 
What do you plan on making? That's a good place to start. 
You can : 
1. Do nothing and leave it as it is. 
2. Give it a coat of gum tragacanth or the synthetic japanese stuff (tokunol??). The Japanese stuff is better I think. I have seen people use Tan Kote (Ian Atkinson does that), but I am not sure how good it actually works. 
3. Cover it with another piece of leather . A think lining leather like pig might suit your purpose, depending on what that is. If you are making wallets, you could also apply a layer of fabric.