How do I fix my wall?

If it's drywall, you can get yourself a drywall saw at the hardware store and carefully cut out a nice, clean square shape around the damaged area. Get yourself just enough new drywall to replace what you cut out (hopefully one sheet will do) and cut off a piece to fit the square hole you made; hopefully you can screw it to a stud in the wall with a drywall screw or two, sunk just below the surface of the drywall (don't use a screw that isn't coated or galvanized ... it will cause a rust spot later). Shaping the insert piece to perfection is not necessary, but the closer the better. Get some drywall tape or mesh and cover the seams between the wall and the new piece you've inserted. Cover over the tape or mesh with joint compound or "drywall mud," letting it spread liberally over onto the wall and the insert piece. Let dry, then sand smooth, trying to conceal the seams under the compound. It will probably take you several coats of mud and several sandings to make it look just right. When it does, you can paint. With patient, careful work, you'll hardly be able to tell it was ever damaged. But if that's too much work ... hire a handyman!

You'll want to cover the exposed area with drywall mud or spackle first. Apply in thin coats, let dry, sand and repeat until the area is smooth and on the same plane as the rest of the wall (even with it). If the texture of the wall is rough, use a damp sponge after you apply the last layer of spackle or mud to raise up the texture to approximate what the rest of the wall has. Press the sponge into the wet mud or spackle and lift out without any wiping action to try to simulate the other texture. If you can't get that to work, smooth it off again, let it dry, sand it and get a spray can of texture at the home product store. Once the wall is even and textured to match, then you can paint it to match the color of the rest of the wall.

good luck!

You must cut the damaged area evenly, buy at Lowes or Home Depot the same thickness dry wall and attach to it. Most of the stores sell pre cut small pieces if you prefer rather than buying a 4 X 8 feet sheet. To attach, you must use four pieces of backing thin wood (like 1 X 3") fastened behind the old dry wall with screws showing half of the wood area around the perimeter to attach the new piece with dry wall screws as well. Attach the new piece evenly, cut a small deep canal between the old and the new dry wall in angle, with a plaster knife apply a coat of compound, lay dry wall tape nice and flat, and spread another coat on top of the tape nicely even. Allow compound to dry, slightly sand it without damaging the tape, apply coats as needed, allow to dry between coats, sand and apply coats as needed. When the surface is nice and even, apply few coats of latex white primer with a roller allow surface to dry

You have to cut out the area that got wet otherwise it will probably mold up on you and then once that happens your minor repair becomes a major repair.

Cut a square hole in the wall ending half way on the studs. Give it a couple days to dry out. If mold is present spray it down with bleach diluted with water. Home Depot/Lowes sells 2'x2' pieces of drywall to patch the hole.

not sure how large an area or the extent of the damage, however the best practice is to cut out the damaged sheetrock area. Normally to the next stud or nailing surface, in a square or rectangular shape. Measure and cut in a new piece and screw it in. Then patch with tape and compound.

Sand and paint.

If your painting on bare plaster then you need to put a Primer coat on first to stop the topcoat soaking into the Plaster.

you may desire to drill a hollow interior the wall for the wall plug to greater healthy into. The drill bit needs to be the main appropriate length so the plug is a good greater healthy after which you screw the screw into the plug.

spackle or repalce wall.