What did you spray it with?

1) Keep the grass mowed and watered. It will eventually fill in.

or

2) Till & re-seed the burnt patches.

With dry weed and feed products there can be problems if it doesn't rain. You will have to rake out the dead grass. It might regrow but sometimes reseeding right away is not recommended if it is a liquid weed killer. Check the bottle or packet. Go onto their website and see if they can suggest what to do next.

Hi Bamboo, I should have said it was Weeds I sprayed and I used
Resolvable 24hr

As far as I'm aware Resolva 24H is a systemic, none selective weed killer, which means it will kill ANY plants, including grasses that it comes in contact with.

For weeds in lawns you need to use a selective broad leaf weed killer that will kill weeds but won't harm the grass.

However, all is not lost. It looks like you have used Resolva to spot treat your lawn rather than applying it all over the lawn. It doesn't look too bad, so as soon as the application has dried off you can replant as it's systemic so the soil won't be affected. If you applied it in the last few days and want to reseed your lawn now, I would give it a good watering to wash any weed killer away to be certain.

Resolva also make a Lawn Weedkiller in a spray which doesn't kill grass, so that's the one you should have used.

Recommend you wait a week (assuming you have rain, which would be good) then prepare the bald patches by creating a tilth on the top inch or two inches, level and reseed with lawn seed. Its said you can replant immediately after using Resolva 24, but they mean actual plants, not seeds, so just wait a total of a week from when you sprayed. If that's already a week ago, then prepare the areas now for reseeding.

Thanks for all the replies, I will use the advice well ☺ but I must Read the labels on the stuff I buy with greater detail ?