Welcome criticism, and listen closely to it, but don’t agree with everything that’s said about you or your writing.
There’s a fantastic saying that goes, ‘To avoid criticism say nothing, do nothing, be nothing.’ Any time you say, do or be anything people will criticise you. Sometimes they’ll be genuinely trying to help you, but other times they’ll just be putting you and your work down (n.b. this can include people you are close to, even some who love you!). Learn to know the difference between helpful and unhelpful criticism – and don’t listen to the unhelpful stuff.
Having said that, don’t assume that if the criticism is painful to hear that it’s unhelpful. Sometimes the painful stuff is exactly what you need to hear. So listen closely to criticism and restrain yourself from getting defensive or dismissive – but then quietly work out if it’s been helpful or not. Or both.
The real trick to processing criticism is knowing what’s worth listening to and what should be ignored.