Some screen damage is obvious the moment it happens. Other faults creep in slowly: a corner that stops responding, a faint line that gets longer, a flicker you only notice at night. Here's how to tell what you're dealing with and when it's time for a professional opinion.
Visible cracks: how serious are they?
A phone screen is made of layers. On top is the cover glass you touch. Beneath it are the touch layer and the display panel that produces the image. A crack can affect just the top layer, or go deeper.
Is it the screen protector or the actual screen?
Before anything else, check whether you have a screen protector fitted. Protectors often crack on impact and save the glass underneath. Look along the edges of the screen for a slight lip, or gently run a fingernail across the crack. If the crack sits in a separate thin layer that you can see lifting at a corner, replacing the protector may be all you need.
Why small cracks still matter
- Cracks usually spread with everyday knocks and temperature changes.
- Splintered glass can cut fingers and faces, especially near the edges.
- Gaps in the glass let in dust and moisture, which can damage parts underneath.
- A crack over the front camera or sensors can affect face unlock, auto-brightness and the screen turning off during calls.
If a crack is small and the phone works normally, you may choose to live with it for a while. A clear screen protector over the top can stop splinters, but it won't stop the crack growing.
Touch problems and dead zones
A screen can look perfect and still have a touch fault. Typical signs are an area that ignores your finger, typing that misses certain letters, or "ghost touches" where the phone opens apps or types by itself.
A simple test is to open a notes or drawing app and slowly draw lines across the whole screen, top to bottom and side to side. Gaps in the lines show where touch isn't registering. You can also press and hold an app icon and drag it slowly around every part of the screen; if it drops in one area, that area has a problem.
Rule out the simple causes first: clean the screen, take off the case and screen protector (a lifting protector is a common cause of ghost touches), make sure your hands are dry, and restart the phone. If the fault is still there afterwards, it's likely to be hardware.
Flickering, lines and colour problems
Coloured lines, green or pink tints, black blotches that spread, or a display that flickers at normal brightness usually point to damage in the display panel itself. This often follows a drop, even one that didn't crack the glass, or pressure such as sitting on the phone.
A useful check is to take a screenshot while the fault is showing, then look at the screenshot on another device. If the screenshot looks normal, the problem is in the physical display, not the software. If the fault appears in the screenshot too, it may be an app or software problem, and a restart or update is worth trying first.
Some people notice a faint flicker on certain phones at very low brightness. If that's all you see and it has always been that way, it may be how that display works rather than a fault. A change that appears suddenly, or gets worse, is a different matter.
A black screen on a phone that's still on
If the screen is dark but the phone still rings, vibrates, plays notification sounds or connects to your computer, the display or its connection may have failed while the rest of the phone works. Try calling the phone from another number to check. Then try a forced restart, because a software freeze can also leave the screen black.
If the phone shows no sign of life at all, read our guide on what to do when a phone won't turn on instead, as the cause is more likely to be power-related.
Screen lifting away from the frame
If the screen is being pushed up at one edge, or the phone no longer sits flat on a table, the battery underneath may be swelling. Treat this seriously: stop charging the phone, don't press the screen back down, and get it checked soon. Our guide to phone overheating and warning signs explains why swollen batteries need care.
When a professional assessment makes sense
- The glass itself is cracked, not just the protector.
- Part of the screen doesn't respond after you've cleaned it and restarted.
- Lines, blotches or tints appear, and a screenshot looks normal.
- The screen is black but the phone is clearly still working.
- The screen is lifting, or the phone has been in liquid.
Screen replacement involves adhesives, fragile ribbon cables and sensors near the top of the display, so it's a job to have done carefully. A technician can also check whether anything else was damaged in the same drop.
Before you hand your phone over
If the phone still works, back it up first. Most screen repairs don't affect stored data, but it's sensible to have a copy. See how to protect your data before a phone repair for the steps.
