How to add texture to mesh in runtime?

I create a mesh that can update in runtime using vertex.And i want to change the mesh color in runtime.
Firstly i think about change the vertex color,but i don’t know to change it.
Then,i try to load/create a texture, and add it to the mesh in runtime.
So,i used the function SetMaterial(index,material) in the runtime,successfully i loaded material,but i can’t add texture to the material.

here is my code
reliefMapTexture = ConstructorStatics.TextureFinder.Get();
terrainMaterial = ConstructorStatics.MaterialFinder.Get();
DynamicMaterial = UMaterialInstanceDynamic::Create(terrainMaterial, this);
DynamicMaterial->SetTextureParameterValue(FName(“flexBaconTex”), reliefMapTexture);
RuntimeMesh->SetMaterial(0, DynamicMaterial);

the problem is ,i can just set the material,but can’t change the texture.
what’s the problem?Is there other method to change the mesh color/texture?
please help me!