High Grade Changes

I'm new to here but hope someone can help. I went to my doctor for a regular smear after having LLETZ in 2003 and she said my cervix looked raw and was referring me for a colonoscopy Before my smear results were even sent off. 4 days later I was at the hospital having this done. The doctor took some biopsys by did nothing else and said id have to wait 4 weeks for the results. I was fine about this until my smear results arrived this morning indicating I have high grade dykasosis ( spelt incorrect) and is need a colonoscopy. The doctor at the hospital said when my smear results came through and it said there were any changes and I needed another colonoscopy not to worry because he'd already done it. Last time I had mild changes and they did the LLETZ at the same time as my colonoscopy, this time they are high but he only took some biopsys,why didn't he burn them away, I'm left feeling nervy and unsure what's going on.