Yes, it can. Straightening relies on heat to make hair look straight and shiny, but the effect is only temporary, and the whole process leads to significant damage in the long run. Straightening can make hair rough, dull, and brittle due to the fact it strips your locks of lipids, protein, and it dries out the cuticles. Try to avoid heat styling as much as possible, especially when your hair is blonde because it required a lot of processing (bleaching) to achieve the desired shade in the first place.