All your existing points are inside the system and nothing is lost.
Once you have logged into your account you can click on My Rewards
Or go directly to the rewards page at https://www.skinshop.co.uk/my-rewards
Here you can see how many points you have and collect discount vouchers. Depending on how many points you have you can select what reward voucher you want.
After clicking it you can use the small copy button to copy your voucher code
And use it in the discount box during checkout to reduce your order total.