Teeth whitening!?

[TexasMama]

So I bought a cheap tooth whitening kit on ebay, it was a gum shield with gel and a hand held UV light. After 15 minutes I took the gum shield out and I had chemical burns on my gums, in a few places they had turned a horrible white/grey colour, they looked a bit like I had chewing gum stuck between my teeth! Thankfully they went back to their normal colour and stopped hurting after a couple of days, but I won't be using that product ever again. My teeth were no whiter either!

Can anyone recommend a good tooth whitening product that is not only safe, but actually works? Or is getting it done at the dentist the only option?
Thanks!

I've recently had it done under dentist supervision. Had trays and gel to apply at home. I had the temporary gum issues you had but my dentist was not worried. My teeth are definitely whiter though.

Can I ask how much it cost?

£250. It took 2 weeks. I already had the trays from from my braces though so I don't know if that would increase the price.

I had it done with the trays and bleach supplied by my dentist. It was a fairly long process wearing the trays overnight every other night for at least 6 weeks but it was worth every penny. My teeth have never been very white but they are whiter than they have ever been. I even had friends commenting. Cost a few hundred quid and I buy extra bleach syringes as and when just to top up.